Features: - Built-in 2.4G ultra-long-range wireless flash system Global free application for digital FSK 2.4GHz & ultra-long-range-distance wireless transmission modulecommunication distance can up to 50 metres. - The speedlite could be the Master unit (accept the flash from the main control unit and to achieve the desired flash)supports 10 channelsthree different groups to achieve multi-lamp creative cloth light system. - TR series: High performance high compatibility high-power flash output. - Increases the external power outlet: TR series adds an external power outlet; call back the higher rate to meet your needs. - Quick call back: Full output only 2.9 seconds recycle time do not apply the new battery can also call back to obtain a rapid rate only 4-5 seconds. - Supports high-speed continuous shooting: 1/16 and below the brightness TR series to support high-speed continuous shooting 12SEPS. - Power-saving mode: When the flash without any action on the backlight turned off after 20 seconds 60 seconds when the flash does not work CPU automatically goes to sleep does not work more than 30 minutes CPU will automatically shut down. High-precision output: From 1/128 to 1/1 8 stalls to lose each stall have two fine-tuning compensation. - Overheat protection: Built-temperature detection (thermal protection) Flash mode: Without Automatic AF(assist lamp); Manual mode; Repeating flash mode; Semi-automatic flash mode. Specifications: - Guide number:56 meters (ISO 100 180mm). - Circuit design:Insulated Gate Bipolar Transistor (IGBT). - Flash mode:MasterSlaveS1S2Multi. - Zoom range: 18~180mm Manual Zoom Swinging/Tilting flash head(bounce flash). - Vertical rotation angle:0 to 90 degree. - Horizontal rotation angle:0 to 360 degree. - Power: 4 x AA Batteries(Alkaline or Ni-MH are usable). - Flash control:1/128~1/1 step length is 0.3EV Total 22 fine-tuning stalls. - Recycle time: approximately 3s (AA alkaline cell used). - Lighting time:100-1500 times (using AA alkaline cell). - Flash time:1/200s~1/20000s. - Wireless triggering distance:20-30m indoor 10-15m outdoor. - Additional function: PC synchronous sniff mode over temperature protection. - Dimensions: 200 x 75 x 57mm(extended state). - Net Weight: 400g. - Compatible for Sony DSLR camerasa77 a55 a65 a57 a33 a900 a700 a500 a350 a300 a200 a100 a850 a580 a560 a550 a500 a450 a390 a380 a330 a290 a230etc.