after much deliberation I ordered this part of Walimex and it also came just one day before I wanted it well and test use. Have on the said day 400 photos shot with flash and the instrument will show no signs of slowing. All 4 green indicator lights are still on. Let's see how long that lasts so. So far I can only say that the device is just great. Use it with a Nikon D7000 and SB 900