This rather unusual accessory, looking like a small hip-flask is in fact a container for batteries. It was made for the LOMO-214, 216 & 218 and the Avrora 215,217 & 219 cameras. These cameras have a socket (like a PC flash socket), so that the internal batteries can be supplemented with additional battery power. The ShP-101 takes five A316 (AA) batteries.

David Tomlinson.