This review is for Nilight - 60001F-D LED Light Bar 8PCS 4Inch 18W LED Bar 1260lm Flood Led.The main mounting screw is an M8 with a 13.5mm wrench flat, which isn't really a wrench size. The angle tilt screw is an M6 with 9.45mm wrench flats, which is pretty much a 3/8". the Side adjustment slot is about 8.25mm wide which allows the 12mm diameter washer to just fall in if you're not careful. I very much suggest purchasing larger washers before attempting to use these so you don't damage the slot.I tested it with a lab power supply. At 9V it was fairly dim, at 10V a bit brighter. Everything from 11V and up was about the same full brightness. These specify 18W, I expected it to be somewhere between 16W and 20W at full power, these topped out at about 10.6W, or around 60% of spec'd power. I have no way of testing brightness, so I don't know if these are 60% of spec'd brightness as well, or just more efficient than documented.voltage amps watts09.0 0.199 1.79110.0 0.636 6.3611.0 0.967 10.63712.0 0.885 10.6215.0 0.699 10.48518.0 0.574 10.33221.0 0.485 10.18524.0 0.418 10.03227.0 0.367 9.90930.0 0.326 9.78