The PocketWizard Plus is the result of 10 years of experience building sophisticated remote triggering devices for photographers. All PocketWizard's use the most advanced digital radio system in the photographic industry to deliver impressive range and reliability for the professional photographer. They can be used to remotely fire your strobes or trigger your camera, effectively becoming a 1600 ft. long cable release. Complex 16- bit digitally coded radio signals deliver a unique code ensuring the receiver cannot be triggered or locked up by other radio noise. The built-in microprocessor guarantees consistent synch speeds even under the worst conditions. The transmitter & receiver operates on 2 AA batteries (included) & provide uninterrupted use for up to 250-hours. Each PocketWizard Plus transmitter & receiver have 4 user selectable digital channels, enabling multiple photographers to work in the same shooting environment.