"As this has an angle grinder fitting I assumed it would work on an angle grinder. It doesn't!!. I just ripped it'self apart in an instant. There is no advice anywhere on the Screwfix site for a max speed. However, embossed in the plastic is a Max speed of 4600 rpm (it does not warn you on the packaging). My angle grinder goes at 11,000 rpm. I am not sure what tool this is designed for but NOT for an angle grinder. I will see if Screwfix take this back."