Pixel King Pro i-TTL Flash Trigger Receiver for Nikon FSK 2.4GHz wireless remote control system; Remote control distance 300m or above 15 fixed channels and 1 automatic channel; High sync speed up to 1/8000s A, B, C group, 7 combinations allows multiple triggering at the same time King X has USB socket and PC socket for studio strobe, speedlite and outdoor flash. Multiple receivers can be controlled by one King pro transmitter (need separate purchase)