These tuners have a very minimalistic look because they don't use mounting screws to prevent them from rotating. Instead, there are two small pins underneath the housing. It's a clever design but it makes the installation extremely complicated. It is very difficult to drill the holes for the pins in the right places without a template (which is not provided). Despite that, they are really nice tuners. They turn smoothly and hold the tune reasonably well. I've had them for a while and never experienced any problems.