Flash Trigger PT-04 AC Specifications: - 2 channels with hot shoe connector for external flashes - Transmitter Power: 23A 12V battery - Receiver Power: 110-220V AC power - Maximum Working Distance: 30m (open area, without interference) - Operates on Frequency: 433MHz - Highest responding time up to 1/320s - Standby time: one year - Triggering life: up to 20,000 times - Package Included