Specification:Guide No.: 31(ISO 100,105mm)Flash Model: TTL, M, MultiTrigger Mode: On-Camera, 2.4G Radio Trigger, Wireless Optical TriggerZoom Range: 24, 50, 70, 105mmVertical Rotation Angle: -7 to 90 degreesHorizontal Rotation Angle: 0-270 degreesPower Supply: 2 * AA alkaline battery or AA Ni-MH battery(not included)Flash Times: Approx. 220 timesRecycle Time: Approx. 2 seconds(with AA Ni-MH battery)Color Temperature: about 5600KFlash Time: 1/350s to 1/20000sFlash Control: 8 level of output control(1/128-1/1), 22 levels of fine tuning in totalExternal Interface: Hot Shoe, Micro USB PortTransmission Distance: 20-25m indoors, 10-15m outdoors for photo sensitive, up to 100m for radio triggeringAdditional Functions: Lamp head electric zoom, sound prompt, power saving mode, overheating protection, auto-save settingsItem Size: 4 * 6.5 * 15.4cm/ 1.6 * 2.6 * 6.1inItem Weight: 225g/ 7.9ozPackage Size: 19.5 * 9.5 * 8.5cm/ 7.7 * 3.7 * 3.3inPackage Weight: 400g/ 14.1ozNote:In Multi Mode/ radio flash shooting mode/ S1/S2 wireless flash mode, HSS is not supported. Features:Wireless Transmitter-receiver, Supports 2.4G Radio Triggering and Optical Triggering:--YN320EX is compatible with YONGNUO RF602/RF603 radio triggering signal and Sony optical transmission wireless triggering signal, and it can be used as a master unit or slave unit.High-speed Sync TTL Speedlite & Ultra-fast Charging Recycle System:--YN320EX supports TTL flash flash and high-speed sync(HSS). The maximum sync speed is up to 1/8000s; the recycling time for full output just takes 2s, high-speed charging recycling experience for you.Can Realize 6-group Flash Control Easily:--As a radio master unit, YN320EX supports controlling 6 separate groups. It can remotely control the flash mode, flash output, focal length, number of stroboscopic and stroboscopic frequency of YN560Li/Yn720/YN685/YN560III/YN560IV/YN660/YN860Li.Sound Prompt System & Flash Head Electric Zoom:--When the sound prompt system is enabled, the flash emits different sounds to indicate different working status; with ZOOM button, the flash head can circularly move in the coverage rang of 24mm-105mm.USB Firmware Upgrade:--YN320EX is equipped with USB port. The latest firmware can be download from the YONGNUO official website. Upgrade the firmware of YN320EX to keep it in best performance.