The single space F10 (flat) keys measure 0.715" square and are 0.330" tall. 

The mount stem is slightly recessed below the skirt of the key meaning the keycap will sit lower on the Cherry MX switch than a standard DSA, SA or DCS keycap.

F10 keys are available in 1 space, 2 space with 3 mounts, and 2 space with 2 mounts (POS). They are only available as blank keys.

Ortho Base Set includes:

     42 - 1 space
     1 - 2 space (3 mounts)
     1 - 2 space (POS 2 mounts)

Ortho Modifier Set includes:

     20 - 1 space
     1 - 2 space (3 mounts)
     1 - 2 space (POS 2 mounts)