Pixel Opas Flash Trigger Transceiver for Nikon Digital Camera (400M Operation Distance) Opas is a professional grouping flash transceiver which can be activated off-camera trigger, off-camera flash group control and shutter remote shooting. It can be used as Pixel King's receiver (does not support TTL and HSS) Opas also activate the camera shooting and flash trigger together. Studio flashes as well as compact flashes are triggered in manual mode, Opas supports 3 different groups and 4 channels. Uses global free FSK 2.4GHz and is compatible with high voltage flashgun and studio flashes, uses 2 standard AA batteries and also the USB socket for power supply. Operation range: 400M, Max. sync speed: 1/320S; Shutter release: single shoot; Sockets: PC sync, 3.5mm, USB; Trigger method: hotshoe