3M 28405 angle grinder provides 1 hp. Most of the items in this category have a maximum RPM. The maximum RPM is designated for both safety and as the upper limit for performance. In this case the maximum RPM is 12,000. When buying power tools or abrasive accessories pay close attention to the diameter of the tool for supported diameters of accessories and abrasives. This item has a 4 1/2 in diameter.