The Expo Police Camera is an early 20th-century subminiature still camera made by Expo Camera Co., designed in the form of a pocket watch so it could be concealed in the palm of the hand. It was marketed for discreet photography and used small roll film loaded into a dedicated cassette, with the lens hidden behind the winding crown.

Sales history for this model is thin, but at UK auction the two recorded hammer results sit at £168 and £458, giving a wide range of roughly £170–£460 with a midpoint around £310. Condition, completeness of the original film cassette, and presence of the maker's case heavily influence what one of these sells for today, and the scarcity of clean examples explains why the price spread is so large in the auction market.