Thank you Iankat! It does clamp into the guide rail and work universally with the Oregon 410-120 grinder. Dressing depends on how much bar oil you have on your chain. If you clean off the chain you can get quite a bit more teeth out of it before dressing. A bar with lots of oil, which is usually the case you can get about 3-6 teeth done before dressing. The dressing is quick and easy with a diamond file. As far as china goes if you were to knock off a patented product why not knock off the Simington or Silvey grinders? You don't see knockoff of those running around. Sure, china can make cheap knockoffs but I'm not sure that someone would want to spend their money on something that has zero customer service or accountability for the products not working. Squarejig is made in USA with 100% US steel.