Hi Larry

>Is there a native function to restrict the letter to either A or P? using an input mask of 99:99A

Use this input mask: ##:##A with "R" in the formatt property. Then put this in the KeyPress event:

LPARAMETERS nKeyCode, nShiftAltCtrl

if not inlist(nKeyCode, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 97, 112, 65, 80)
	nodefault
endif

This what your looking for?