What would be the battery to run a small clock? The old battery was removed so don't know what it was but think it could have been a CR-2??

Hi Stu, As someone who owns several different kinds of battery operated clocks, my guess would be that yours, like most, takes a "single cell" battery of some standard size. "Single cell" batteries are about 1.5 volts. The CR-2 is a double cell battery (3 volts). If you could get a CR-2 to make contact in the battery holder of your clock, the higher voltage would most likely instantly destroy the clock's electronics. It might be that if you shine a flashlight on the battery holder, you would find that the battery type is molded into the plastic somewhere. The likely type would be a "AAA" or "AA" or "C cell" (all 1.5 volts) and your clock might require more than one of any of those types. If you can't find the battery type notated on the holder, take a close look at what space is available in the holder for each battery to fit and touch the + and - battery contacts simultaneously, then go to a store and buy the battery (or batteries) that look most likely to fit (as long as they are 1.5 volts). By the way, I use my CR-2 batteries to power a combo laser pointer and flashlight.