With a guide number of 213, the SK400II Studio Strobe from Godox is a 5600K daylight-balanced flash source that offers solid core and convenience features at a budget-friendly price point. The head features a 0.4-3 sec recycling time with flash durations as short as 1/2000 sec. Power is variable from 1/16 to full power, adjustable in 40 steps, while the 150W modeling light has a Proportional mode to allow you to preview your lighting effects and a Percentage mode that adjusts brightness from 5 to 100%. Settings are accessed via rear panel push buttons and displayed on the easy-to-read LCD screen. Triggering options include sync cord, test button, and slave triggering. The SK400II has a built-in 32-channel X1 radio system, making wireless function control possible with separate purchase of the XT16, FT16 or X1 TTL transmitter. The head also has an anti-pre-flash function that makes it easy to work with point-and-shoot and other cameras that employ pre-flash. The SK400II weighs in at 4.6 lb, encouraging the assembly of a kit with two or more heads without having to lug a heavy case around. The SK400II has a Bowens front accessory mount, allowing it to use Godox modifiers as well as accessories from the many manufacturers that use this system. The head has a tilting stand mount and runs on 100 to 120 VAC mains power.Built-In 2.4 GHz Wireless X SystemUse TTL wireless trigger X1 as well as power remotes XT16 or FT16 to wirelessly control the head's power, modeling light, triggering, and more. The system has 32 radio channels and 16 groups.Fast Recycling and Flash DurationThe SK400II features 0.4-3 sec recycling and 1/800 to 1/2000 sec flash durations.Precise Power AdjustmentPower can be adjusted from 1/16 to 1/1 in 40 steps. The 150W modeling light has 3 modes: Off, Proportional, and Percentage (5 to 100%)InterfaceKeyboard and multi-function buttons. The LCD screen displays settings and functions.