Special aluminum oxide formulation prevents ??????????oading??????????on soft (non-ferrous) metals.Soft bond for aggressive removal of material without loading.Outlasts competition by as much as 40%.Type 27., Special aluminum oxide formulation prevents "loading" on soft (non-ferrous) metals.All sizes internally reinforced with the highest quality fiberglass for maximum safety and performance.Our unique Super-Lock??????????Hub combines both a mechanical locking system and chemical bond providing one of the safest, vibration-free designs in the industry.See Cotton Fiber Products for more products for Aluminum.