The quantum qflash pilot qf9c provides all the features of the qflash trio just without the flash head the self powered 4x aa batteries pilot commands remote qflash requiring no external power pack and mounts to a hot shoe on a canon dslr the pilots radio trigger sends ttl commands to remote qflash trios and older qflash models mated to freexwire receivers and you can control an unlimited number of remote qflash units radio qttl signals from the pilot do not require line of site like ca