I have them and they are excellent, the best chain adjusters, +1 to what milbridger says.
There is another brand from china (4racing) that look almost the same as the lightech ones, but cheaper. I first bought the 4racing ones and then returned them to the UK supplier. I would recommend buying the lightech as they are good quality and well designed.
I think it's either Lightech or Gilles...if you want quality. And when it comes to making sure your axle is straight and the chain adjusted well...some might call it VFM.