Wein Products W920200 SSR Open Channel High Power System Consists of: SSR OPEN-CHANNEL SLAVE TRIGGER (W918200) With color-coded on/off switch. Battery saver circuit for 5000 shots on "AA" alkaline cells. SSL ULTRA SLAVE "H"-PRONG RECEIVER (W930010)With standard "H"-prong and "PC" connectors. Two Velcro strips for mounting when using PC cord. 1-1/2 x 2-1/2 x 7/8" 1.1 oz. Supplied with: 10" Miniplug-to-PC cord for non-hot-shoe cameras. Extra Velcro strip. Batteries: Requires two "AA" alkaline for transmitter (not supplied). Infrared technology 300 ft. range Includes both transmitter and receiver