To permit auto TTL off-camera photography it requires EOS connecting cord 300 or 60 and off-camera shoe adapter 2 or TTL distributor and connecting cords for multi-flash photography. It is placed in the EOS camera's accessory shoe, this device controls up to 4 off-camera speedlites.

Note: This accessory provides TTL or manual flash control, but is not compatible with E-TTL and will not support automatic flash on digital SLRs