I own and use this great phone set. Here is the manual. RA2184BB is the model on the sticker on the base. RA218 is the model on the cover of the manual. The handsets don't have a model on them as far as I can tell. Replace the batteries with NiMH AA cells. And these things will last FOREVER. I replaced batteries in four handsets for 12 dollars. (And had the batteries delivered to my door.)