Radio Slave 4i improvements over the model 4 are as follows:
* The range has been extended to 350 feet (110 meters)
* With the 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
* 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".
*** Radio Slave 4i maintains these features:
Trigger any number of remote flashes without a sync cord.
* Trip a motor drive camera, or a remote power pack at great distances. Unlike other types of slaves, Radio Slave 4i cannot be overpowered by the light of a flash.
* Status lights on both Sender and Remote confirm proper operation and/or low batteries.
* Superior interference free reception.
User selected coded channels permit many Radio Slaves to operate in the same area.
* Radio Slave 4i is compatible with the Radio Slave 4 and Radio Slave 2.
***** Be sure to match the labeled frequency (either A, B,C, or D) with your previous units.