DEFINATLY HANDSPRING ,,THEY HAVE THE EXPANSION SLOT FOR OTHER STUFF ,, VISOR DELUX AND NEO ARE WHAT I USE , DONT GET COLOR ,,THEY ARE HARD TO READ IN THE DAYLIGHT ,, AND DONT GET THE ONES THAT HAVE RECARGABLE BATTERYS , I FOUND THAT IF THEY GO DEAD ON THE JOB ... Login to read more.