Features: 1. M Mode Press the MODE key to M Mode. In this mode, you can set the TT560 to your camera hot shoe or speedlite trigger hot shoe to trigger the flash unit. When shooting, adjust the flash power and press the camera shutter, the flash light will flash under the camera synchronous signal. 2. S1 Mode: Press the MODE key to S1 Mode. The Mode is applicable for slave flash in order to create many lighting effects. It is respectively applicable for manual flash environment. When the flash is S1 mode, it will fire synchronously when the master flash fires, comparable with the effect by the use of radio trigger. 3. S2 Mode: Press the MODE key to S2 Mode. The mode is applicable for slave flash in order to create many lighting effects. It is respectively applicable for TTL flash environment. The flash unit won"t flash synchronously with the first flash but the second flash from the master flash. 4. Power-saving Function: To save battery power, the flash will enter stand-by state in about 30 minutes of idle use. Press any button to wake it up. In S1/S2 mode, the flash will enter stand-by state in about 60 minutes of idle use. Press any button to wake it up. In Power-saving mode, the charging indicator flickers in every 3 seconds. 5. Protection Function (1) Protection in continuous flashes (2) Systematic over-temperature protection.Specifications: Guide Number:38 ( ISO 100 ) Flash Mode: M, S1, S2 Vertical Rotation Angle :0~90 degrees Horizontal Rotation Angle: 0~270 degrees Power: 4xAAsize batteries ( Alkaline or Ni-MH are usable ) Lighting Times: 100-1500 times ( AA alkaline batteries used ) Recycle Time :approx 0.5-5.5s ( AA alkaline batteries used ) Light Quantity Output Control :with 1/8 - stop increment Color Temperature: 5600K Flash Duration :1/300s~1/20000s