The Meter Mate 2 Transmitter eliminates the need for a PC hookup to your flash meter when taking exposure readings. Attach with Velcro to your flash meter, plug into the PC terminal, then connect a Wein SSL Ultra Slave (at least one required) to the main flash. Each time you press the flash meter exposure button, Meter Mate 2 emits an invisible pulse of infrared light that fires your entire slaved flash setup, cordlessly, from up to 100 feet away. Transmitter comes with a replaceable battery that powers up to 6,000 firings. An ideal addition to SSR/SSR-jr. Studio remote systems.