The ELB 400 Quadra Pack is run off a rechargeable Li-ion battery that can deliver an impressive 424 Ws of power and recycle as fast as 1.6 seconds at full power. It features an integrated EL-Skyport receiver, which is compatible with the included EL-Skyport Transmitter Plus. This transmitter allows you to trigger and set flash power for up to four groups, as well as an all groups setting, and 16 different channels, which are split between eight normal channels and eight hi-speed channels. A locking metal accessory shoe connector allows you to secure the transmitter directly to a camera, while a top hot shoe and a 2.5mm sync port are available for directly connecting an additional strobe, and a swiveling design helps to improve reception for more direct transmission.