- key: 0
  name: instance_uuid
  type: uuid
  description:
    - Unique identifier of the package instance.
    - If not specified, can be deduced from NFC tag UID.
    - See _UUID_ section for more details.

- key: 1
  name: package_uuid
  type: uuid
  description:
    - Universally unique identifier of the package (product)
    - If not specified, can be deduced from `brand_uuid` + `gtin`.
    - See _UUID_ section for more details.

- key: 2
  name: material_uuid
  type: uuid
  description:
    - Universally unique identifier of the material.
    - If not specified, can be deduced from `brand_uuid` + `material_name`.
    - See _UUID_ section for more details.

- key: 3
  name: brand_uuid
  type: uuid
  description:
    - Universally unique identifier of the brand
    - If not specified, can be deduced from the `brand_name` string.
    - See _UUID_ section for more details.

- key: 4
  name: gtin
  type: int
  required: recommended
  description: Global Trade Item Number.

- key: 5
  name: brand_specific_instance_id
  type: string
  max_length: 16
  description:
    - Brand-specific identifier of the package instance.
    - Not much use cases at this moment, possibly just for URL deduction

- key: 6
  name: brand_specific_package_id
  type: string
  max_length: 16
  description:
    - Brand-specific identifier of the package (product ID).
    - Not much use cases at this moment, possibly just for URL deduction

- key: 7
  name: brand_specific_material_id
  type: string
  max_length: 16
  description:
    - Together with brand uniquely identifies each material.
    - Not much use cases at this moment, possibly just for URL deduction.

- key: 8
  name: material_class
  type: enum
  required: true
  example: FFF
  items_file: material_class_enum.yaml
  display_name_field: description

- key: 9
  name: material_type
  type: enum
  category: fff
  items_file: material_type_enum.yaml
  name_field: abbreviation
  display_name_field: name
  required: recommended
  example: PC
  description:
    - Coarse classification of the material.
    - Useful for determining default parameters for preheat an such that are not explicitly specified in the data.
    - If the material does not match any of the proposed material types, can be left unspecified.

- key: 10
  name: material_name
  type: string
  max_length: 63
  example: PC Blend Carbon Fiber Black
  required: recommended
  description:
    - Brand-specific material display string/identifier.
    - In the UI, brand_name + material_name should be displayed together, for example "Prusament PLA Galaxy Black".

- key: 52
  name: material_abbreviation
  type: string
  max_length: 7
  example: PCCF
  description:
    - Abbreviation of the material name, for UI purposes (footers, dashboards, ...).
    - If not present, the material inherits the abbreviation from the material type.

- key: 11
  name: brand_name
  type: string
  max_length: 31
  required: recommended
  description: Brand of the material.
  example: Prusament

- key: 12
  deprecated: true

- key: 13
  name: write_protection
  type: enum
  items_file: write_protection_enum.yaml
  description:
    - Indicates whether the tag is write protected (everything except aux section, that one should be always writable).
    - See the _Write protection_ section.

- key: 14
  name: manufactured_date
  type: timestamp
  required: recommended

- key: 55
  name: country_of_origin
  type: string
  max_length: 2
  description: Country the [MaterialPackageInstance](terminology) was produced in, encoded as a two-letter code according to [ISO 3166-1 alpha-2](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2).

- key: 15
  name: expiration_date
  type: timestamp

- key: 16
  name: nominal_netto_full_weight
  required: recommended
  type: number
  unit: g
  example: 1000
  description:
    - Nominal/advertised weight of the full package of the material, excluding the container.
    - The actual netto weight of a specific package instance can slightly differ and is specified by `actual_netto_full_weight`.

- key: 17
  name: actual_netto_full_weight
  required: recommended
  type: number
  unit: g
  example: 1012
  description:
    - Actual weight of the full package of the material of this specific package instance, excluding the weight of the container.
    - Can slightly differ from `nominal_netto_full_weight`.
    - If not present, `nominal_netto_full_weight` SHALL be used as a fallback.

- key: 53
  name: nominal_full_length
  required: recommended
  category: fff
  type: number
  unit: mm
  example: 350000
  description:
    - Nominal/advertised filament length of the full spool.
    - The actual length of a specific package instance can slightly differ and is specified by `actual_full_length`

- key: 54
  name: actual_full_length
  required: recommended
  category: fff
  type: number
  unit: mm
  example: 351000
  description:
    - Actual filament length of the full spool.
    - Can slightly differ from `nominal_full_length`.
    - If not present, `nominal_full_length` SHALL be used as a fallback.

- key: 18
  name: empty_container_weight
  required: recommended
  type: number
  unit: g
  description: Weight of the empty container.

- key: 19
  name: primary_color
  type: color_rgba
  required: recommended
  example: "`\\xff\\x00\\x00\\x7f`"
  description:
    - Primary color of the material in the RGB(A) format, intended for UI purposes.
    - The alpha channel can be left out, in which case the data should have 3 bytes instead of 4 and the color will be considered fully opaque.
    - If a material doesn't have a single primary color (for example rainbow or coextruded filaments), this field SHOULD be omitted.

- key: 59
  name: primary_color_lab
  type: color_lab
  unit: '[L*, a*, b*]'
  example: '[53.24, 111.12, -27.3]'
  description:
    - "Color of a material in the device-independent CIE L*a*b* (CIELAB 1976) color space with reference white D65/2\xB0."
    - If present, the value MUST be obtained by physical spectrometry measurement; it MUST NOT be approximated (for example from RGB).
    - "`L*` is bound to [0, 100], `a*` and `b*` values are dimensionless and are typically between \xB1127, but can theoretically get in the \xB1150 range."

- key: 60
  name: primary_color_ral
  type: string
  unit: RAL code
  max_length: 16
  example: 270 30 20
  description:
    - RAL color identifier, without the "RAL" prefix.
    - The value MUST correspond exactly to an official identifier (see https://www.ral-farben.de/en/all-ral-colours).
    - If present, the physical material MUST match the referenced RAL swatch; it MUST NOT be approximated (for example from RGB/LAB).
    - 'Examples of valid values: `3020`, `9005`, `1023`, `7016`, `270 30 20`, `190 50 35`, `530-1`, `850-M`, `P1 3020`.'

- key: 20
  name: secondary_color_0
  type: color_rgba
  description:
    - One of secondary colors of the material.
    - Data format is the same as for `primary_color`.

- key: 21
  name: secondary_color_1
  type: color_rgba
  description: See `secondary_color_0`.

- key: 22
  name: secondary_color_2
  type: color_rgba
  description: See `secondary_color_0`.

- key: 23
  name: secondary_color_3
  type: color_rgba
  description: See `secondary_color_0`.

- key: 24
  name: secondary_color_4
  type: color_rgba
  description: See `secondary_color_0`.

- key: 25
  deprecated: true

- key: 26
  deprecated: true

- key: 27
  name: transmission_distance
  type: number
  example: 6.6
  unit: HueForge TD
  description:
    - Transmission Distance is a number representing material opacity.
    - Value ranges from 0.1 (least transparent/most opaque) to 100 (most transparent/least opaque).
    - See [Prusa TD values](https://help.prusa3d.com/article/hueforge-filament-transparency-values-and-hexcodes_762314) or [HueForge website](https://shop.thehueforge.com/blogs/news/what-is-hueforge).

- key: 28
  name: tags
  type: enum_array
  max_length: 16
  items_file: tags_enum.yaml
  example: "glitter + dual_color"
  required: recommended
  description: Properties of the material. Can have multiple tags at once.

- key: 56
  name: certifications
  type: enum_array
  max_length: 8
  items_file: material_certifications_enum.yaml
  example: "`ul_2818`"
  description: Certifications the material has.

- key: 29
  name: density
  type: number
  unit: g/cm³ (1 g/cm³ = 0.001 g/mm³ = 1000 kg/m³)
  example: 1.24
  required: recommended
  description: Density of the material.

- key: 30
  name: filament_diameter
  type: number
  unit: mm
  example: 2.85
  category: fff
  description:
    - Diameter of the filament, in mm.
    - If not present, 1.75 mm is assumed.

# Removed 18

# Removed 19

- key: 31
  name: hardness_shore_a
  type: int
  example: 95
  description:
    - Hardness of the material on the Shore A hardness scale (suitable for softer materials).
    - "**Note:** There is no 1:1 mapping between A and D scales, different materials can have different values on one scale even though they are the same on the other."

- key: 32
  name: hardness_shore_d
  type: int
  example: 30
  description:
    - Hardness of the material on the Shore D hardness scale (suitable for harder materials).
    - "**Note:** There is no 1:1 mapping between A and D scales, different materials can have different values on one scale even though they are the same on the other."

- key: 33
  name: min_nozzle_diameter
  type: number
  example: 0.4
  unit: mm
  category: fff
  description:
    - Filaments can contain particles that would clog smaller nozzles.
    - This field specifies minimum nozzle diameter recommended for printing this material.

- key: 34
  name: min_print_temperature
  type: int
  unit: °C
  example: 205
  required: recommended
  category: fff
  description:
    - Minimum recommended nozzle temperature for printing.
    - Also used for loading the filament to the nozzle.

- key: 35
  name: max_print_temperature
  type: int
  unit: °C
  example: 225
  required: recommended
  category: fff
  description:
    - Maximum recommended nozzle temperature for printing.
    - Also used for loading the filament to the nozzle.

- key: 36
  name: preheat_temperature
  type: int
  unit: °C
  example: 170
  category: fff
  required: recommended
  description:
    - Recommended nozzle temperature for preheating/load cell bed leveling.
    - Should be large enough for the material to get soft, but not low enough for it no to drip out of the nozzle.

- key: 37
  name: min_bed_temperature
  type: int
  unit: °C
  example: 60
  category: fff
  required: recommended
  description:
    - Minimum recommended heatbed temperature.

- key: 38
  name: max_bed_temperature
  type: int
  unit: °C
  example: 60
  category: fff
  required: recommended
  description:
    - Maximum recommended heatbed temperature.

- key: 39
  name: min_chamber_temperature
  type: int
  unit: °C
  example: 10
  category: fff
  description:
    - Minimum recommended temperature of the chamber.

- key: 40
  name: max_chamber_temperature
  type: int
  unit: °C
  example: 50
  category: fff
  description:
    - Maximum recommended temperature of the chamber.

- key: 41
  name: chamber_temperature
  type: int
  unit: °C
  example: 20
  category: fff
  description:
    - Ideal chamber temperature for printing.

- key: 42
  name: container_width
  type: int
  unit: mm
  example: 75
  category: fff
  description:
    - Width of the filament spool. Can be useful to know for spool holders, dry boxes and such.

- key: 43
  name: container_outer_diameter
  type: int
  unit: mm
  example: 200
  category: fff
  description:
    - Diameter of the spool. Can be useful to know for spool holders, dry boxes and such.

- key: 44
  name: container_inner_diameter
  type: int
  unit: mm
  example: 100
  category: fff
  description:
    - Diameter of the inner cylinder the filament is spooled once.
    - Equals to the minimum diameter of the filament winding.

- key: 45
  name: container_hole_diameter
  type: int
  unit: mm
  example: 52
  category: fff
  description:
    - Diameter of the center hole of the spool.

- key: 46
  name: viscosity_18c
  type: number
  unit: mPa·s
  description: Viscosity of the material at 18 °C.
  category: sla

- key: 47
  name: viscosity_25c
  type: number
  unit: mPa·s
  description: Viscosity of the material at 25 °C.
  category: sla
  example: 80

- key: 48
  name: viscosity_40c
  type: number
  unit: mPa·s
  description: Viscosity of the material at 40 °C.
  category: sla

- key: 49
  name: viscosity_60c
  type: number
  unit: mPa·s
  description: Viscosity of the material at 60 °C.
  category: sla

- key: 50
  name: container_volumetric_capacity
  type: number
  unit: ml (cm³)
  category: sla
  description: Maximum amount of material the container can hold.

- key: 51
  name: cure_wavelength
  type: int
  unit: nm
  example: 405
  category: sla
  description:
    - Wavelength of the light the material has been designed to be cured with.

- key: 57
  name: drying_temperature
  type: int
  unit: °C
  example: 45
  category: fff
  description:
    - Recommended ambient temperature for drying.

- key: 58
  name: drying_time
  type: int
  unit: min
  example: 480
  category: fff
  description:
    - Recommended drying time (at `drying_temperature`).

# Reserved: former filament_diameter_v2 (µm), reverted to filament_diameter (key 30, mm). Do not reuse.
- key: 61
  deprecated: true

# Reserved: former min_nozzle_diameter_v2 (µm), reverted to min_nozzle_diameter (key 33, mm). Do not reuse.
- key: 62
  deprecated: true

# First unused key: 63