Phottix Ares II Wireless Flash Transmitter is used in combination with a receiver to wirelessly fire flashes, compacts and battery pack lighting in any situation. This 2.4 GHz transmitter, when used with the Phottix Ares II receiver, is capable of firing lights up to 490 feet apart. Users will also have access to 16 channels, the first of four of which will also support Strato II receivers as well, and four groups. All settings can be checked via the backlit LCD screen. Max sync speed is 1/250 second.