\useasboundingbox (-1.8,-2.3) rectangle (1.8,2.3);

\tikzstyle{box} = [ draw=black
                  , text width=1.2cm
                  , minimum width=2cm
                  , minimum height=1cm
                  , align=center
                  , rounded corners
                  , thick
                  , align=center
                  ]
\tikzstyle{arr} = [ -{Latex[round,scale=0.9]}
                  , shorten >=1mm
                  , shorten <=1mm
                  , thick
                  ]

\node[box] (ex) at (0, 1.75) {existing tool(s)};

\node[scale=2,inner sep=0pt] (designer) at (0, -1.75) {\faUser};

\node[box] (new) at (0,0) {new tool};

\draw[arr] ($(designer.north)+(0.2,0)$) coordinate (x) -- (new.south-|x);
\draw[arr] ($(new.south)-(0.2,0)$) coordinate (x) -- (designer.north-|x);

\draw[arr] ($(ex.south)-(0.2,0)$) coordinate (x) -- (new.north-|x);
\draw[arr] ($(new.north)+(0.2,0)$) coordinate (x) -- (ex.south-|x);