It cuts through glass, but it's very difficult to start the first cut. There are several defects in the form of protruding lumps of diamond dust on the outer cutting surface, which affect the quality of the cut in the negative state. These bits wear out very quickly and there is no good way to fit them into a drill chuck. The alloy that makes up the racquet appears to be very brittle and the shaft actually broke away from the rest of the racquet after about 8 uses. It was already bent when I…