From Manufacturer
Built for speed, the QT400IIIM Flash Head from Godox is a 5600K daylight-balanced flash source with sophisticated features and advanced technology. The head features 0.01-0.9 sec recycling with flash durations as short as 1/29,600 sec. The QT400IIIM offers power that's variable from 1/256 to full power, while the 40W LED modeling light's output is variable as well. Settings are accessed via rear panel push buttons and displayed on the easy-to-read LCD screen. The head has several flash modes for performance options. Ideal for most shooting situations, Stable Color Temperature mode prioritizes precise 5600K color rendition. High-Speed mode favors short flash durations for ultra-sharp capture of peak action in sports or for creative studio work like freezing splashes or water droplets. The QT400IIIM also supports High-Speed Sync enabling the use of shutter speeds as short as 1/8000 sec allowing you to use wider apertures and other creative effects.
The QT400IIIM has built-in 2.4 GHz 32-channel wireless X technology. Using an optional X1, X2, or XPro transmitter, you can control selection of HSS and High-Speed modes, modeling light modes, remote triggering, and more at distances up to 164'. The head also has S1/S2 slave triggering that makes it easy to work cameras that employ pre-flash. Additionally, the QT400IIIM has a Bowens front accessory mount, allowing it to use Godox modifiers as well as accessories from the many manufacturers that use this system.