Cowboystudio NPT-04, 4 Channel Wireless Hot Shoe Flash Trigger Receiver for Sony Alpha Digital lSLR Camera and Sony Flash

Includes: 1 x Transmitter (with 23A 12V battery installed)
1 x Receiver (Powered by 2 x AAA, Battery is not included)
1 x Sync Wire Cable (no need to use it for most flashes)

4 channels with hot shoe connector for external flashes
Transmitter Power: 23A 12V battery
Receiver Power: 2 AAA Battery (Not included)
Maximum Working Distance: 30m (open area, without interference)
Operates on Frequency: 433MHz
Highest responding time up to 1/320s
Triggering life: up to 20,000 times