The StudioKing TAC04 Receiver is compatible with the StudioKing TRC04H Radio Trigger Set. The TAC04 makes it possible to trigger multiple speedlites in conjunction with the TRC04H Radio Trigger Set. The TAC04 is compatible with all speedlites equipped with a universal hotshoe connection or x-contact (except for Sony/Minolta cameras). The TAC04 is equipped with a ¼” female screw thread. This enables you to mount your speedlite on a light stand or tripod. Further, the TAC04 is equipped with a built-in umbrella holder.