Speedotron Infra Red Sender lets you fire your slaved strobes without triggering flash. No need to hook up a PC cord to the main flash or use a camera-mounted strobe; the SSR transmitter replaces them both. Mount the compact transmitter on your hot shoe, or connect it to the camera PC terminal; each time you shoot, the transmitter fills the studio with an invisible pulse of light.
Note: This is a transmitter only. A receiver is required.