PocketWizard Plus IV Transceiver (2-Pack, Black) with Caddies and Four AA Rechargeable BatteriesPocketWizard Plus IV Transceiver The PocketWizard Plus IV Transceiver is a TTL on camera flash combined with remote manual flash. It has 32 channels (16 standard and 16 Quad Zone). The Pocket Wizard Plus IV eliminates interference with trigger flashes in 4 separate zones, a useful feature for shooting with multiple flashes. Auto Sensing automatically selects the transmitter or receiver mode appropriate to the setup. Auto Sensing also works in tandem