... channels: Single Channel, 2 channels, 4 channels, 8 channels Wireless Flash Trigger 1. DC/AC type, Available channels: Single Channel, 2 channels ... 4 channels, 8 channels. 2. Micro-computer control. 3. Trigger delay is 1/1600 second. 4. Receiver searches channel automatically ... . Receive has the LED indication. 6. Long lifetime of trigger battery(23A): one year, or over 20,000 times continuously ...