This is a Mastery Bridge M2. I was using it comfortably until recently, without any particular problems. It's expensive, but I don't regret buying it. Putting a Mastery Bridge on a Squier would probably make it a great guitar. It can be used on both Fender Jazzmaster and Jaguar guitars, Japan and USA models. There are scratches under each screw from adjusting the octave pitch (see image 3). I am also listing a Japanese floating tremolo unit, so I will discount the shipping if you purchase them together.