Fantastic tool for removing small stumps in the yard.  I used it (cautiously) with a Ryobi 18-volt angle grinder, fearing that my grinder would be underpowered for the job (it runs at 6,500 RPMs) and I would have to invest in a beefier grinder.  The Lancelot is such an effective design that it worked just fine on the Ryobi.  I took my time and was able to whittle down half a dozen small stumps, each about an inch or so high, in no time.  Highly recommend!