This 16-channel receiver is sold separately to expand the capabilities of the Calumet 16-channel Radio Flash Trigger Kit with Digital Readout, which
Includes:: one receiver & one flash transmitter. It requires the 16-channel transmitter for use. This receiver comes with a standard 3.5mm jack. A 6.5mm (1/4") phono jack adapter is included to adapt it to other flash models. The receiver also comes with a PC flash socket, a built-in swivel bracket designed to mount on a shoe adapter with 1/4" -20 female threads (not included) & a hook-&-loop shoe mount to flash. It is powered by a 23A, 12-volt battery, which is included.