The EL-Skyport Transmitter Plus from Elinchrom is a wireless radio trigger with sixteen channels: 8 in normal and 8 in speed mode, with 4 discrete groups for different or sequentially triggered lighting setups at distances up to 656'. Channels 1, 3, and 7 are compatible with all enabled EL-Skyport units, while channels 1, 3, 7, 9, 12, 15, 18, and 20 are only compatible with the ELC Pro HD flash head and the ELB 400 battery pack system. A 2.5mm sync socket extends the transmitter's versatility to cameras without hot shoes or for hard-wired flash units. The EL-Skyport Transmitter Plus runs on easily sourced AA batteries. The transmitter does not come with batteries.