The Dot Line RS-RT05T4C 4 Channel Wireless Transmitter for the RS-RT05T4C wireless kit is an ideal way to eliminate a tangle of PC cords and achieve a studio effect with your shoe mount flash with wireless triggering from up to 85' away. The low profile unit slips quickly onto your camera's hot shoe. This listing is for a transmitter only. A receiver is required for use. See BH# DORSRT05R4C.