Wireless flash sync & wireless shutter release, using up-to-date digital circuitry. Coded radio signal works indoors, outdoors, around corners and through walls. Line of sight is not required between Sender and Remote.
Range has been extended to 350 feet (110 meters) With antenna down, range is up to 200 feet (60 meters)
Hot shoe mount for the Sender. Allows unit to attach to camera shoe, sync cord is not required. Can also be used with provided Quantum sync cord to connect to camera sync. Mount to brackets, dead shoes, etc. with velcro (supplied).
Much longer battery life for Remote unit. With 4 "AA" alkaline batteries you receive up to 400 hours power. (Previously 80 hours for two 9 volt batteries). Up to 800 hours with 4 "AA" Lithium batteries. The Remote can also use AC power with the 515 Adaptor/Charger.
Sync speeds: Normal Mode - 1/250 sec. Focal Plane Sync and 1/500 sec. Leaf Shutter Sync. High Speed Mode - 1/500 sec. Focal Plane Sync and 1/1000 sec. Leaf Shutter Sync. Extremely fast synchronization means Radio Slave 4i is virtually indistinguishable from "wired sync".