Buy on Amazon : br br BELPAIR PT-04NE 4 Channels Wireless Remote Speedlite Flash Trigger with Umbrella HoleHolder br br Power of transmitter 23A 12V mini batteryincluded about one year lifetime Power of the receiverAC 2 15V AAA Alkaline Batterynot included br Outdoor working distance max 30m 90feet open area no fraise Indoor operating distance max 25m 75feet br Channel 4 channels Frequency 433Mhz Synchronous speed Max 1250sec Umbrella socket approx 08cm 024in br Universal hot shoe interface compatible with Canon Nikon Sigma Olympus Pentax etc br Package includes 1 4-channel Transmitter23A 12V battery included 2 4-channel ReceiverAAA batteries NOT included 1 PC Sync Cord25mm to PC 1 User Manual