The Godox X1 Transmitter Set consists of a receiver and transmitter for your external flash unit. This set works with various Godox Speedlite flash units and supports TTL and HHS. The receiver responds to the transmitter within a range of 100 meters. Both have an LCD screen where you can read the settings. Changed settings are saved automatically so that you can easily find them later and use them again. Are you going to work with multiple strobes? The transmitter controls 5 groups.