well, the orginal phones i posted about where older 2554 (I think stromberg-carlson chassis) although the location has approx 250 sets, some desk, some wall, some with dials, some without, different colors for different pourposes, I've gotten to know the "Innards" of the sets pretty well, in the years I have seen that two brands of handsets seem to work best, one is the walker/clarity/plantronics brand and two is the premier handsets from northsupply, as I have a number of local dealers of walker in my area, so if I think wants more then usual I can get it from another, for the wall phones I have tended to have one side or the other of the handset cradel broken off I usually get that from a vendor in texas(thank goodness for henry ford and his interchangeable parts) I tend to avoid the "cheaper" plastic based units, unless I have a compelling reason as if something goes bad, I tend to check the line/handset cord, it's usually one of those two things if it's not one of those two things, I tend to save the cords and get rid of the bad parts, as the plastic units tend not to have much in the way of "serviceable" items in it