Co Pilot is a user friendly wireless TTL Flash Controller With Auto-Focus Assist. Co Pilot (QF91C) for Canon & Co Pilot (QF91N) for Canon DSLR cameras. Photographers can now trigger & quickly set ratios for three groups of radio controlled Qflash. Set lighting ratios on the fly, right from your camera. Simply turn three controls on the Co Pilot to instantly adjust lighting ratios as you shoot. The Co Pilot controls 3 independent remote flash groups without a local flash, or 2 remote groups with a local Qflash connected to the Co Pilot accessory socket. Each flash group can be set to Manual or TTL. Power & ratio settings are easily controlled by a dial for each flash group. Good news for photographers still using their older Qflashes (T2D, T3D T4D, T5D). The Co Pilot gives you the ability to use your old flash as a local flash while still getting the TTL ratio control of remotes offered by the newer T5d R & TRIO. Remote flash groups consist of Quantum TRIO, Qflash T5d R, or any non-Quantum flash that can be triggered in Manual & Auto mode only, by a Free Xwire wireless receiver. Add any number of remotes to any remote group. Mix & match all the flashes you own. Co Pilot controls remote Qflash TRIOs or T5d Rs. & it triggers any combination of non-Quantum flashes connected to a Quantum Free Xwire receiver.