The others are correct. It is a JP precision and to date this is my favorite brake. I have one on my 300 Win pictured below. I have also had them installed on several other rifles. They work awesome and I really like the looks. Another thing I like is that if they are installed so the crown of the barrel lines up with the rear of the first opening it is a simple task to keep the crown clean with out removing the brake. The open design allows this and is a great feature. All blast is directed out and up so no dust storms are created either.
Thanks guys. I appreciate the info, and the reviews. So, you think this break would be good on a 300 RUM? I'm looking for a long-range stick for elk and mulies. This is of course on a used gun, but the price seems about right with the break already installed.