Universal arbor: 1"/20-mm knock out arbor fits all gas and electric high speed saws, 20-mm bushing is pre-mounted into the 1" hole use as is for a 20-mm arbor or remove bushing for a 1" arbor (once bushing is removed, cannot be replaced) Asphalt: Special blend of extra coarse silicon carbide ideal for cutting asphalt, green concrete, wide range of aggregates and abrasive materials; Typical Applications; Cutting sheet metal Cutting pipe Foundry/forge shops - gate/riser removal, cutting forgings Metal plate dimensioning Ship building - metal fabrication Tool room - cutting drill bits, steel bar, tubing, metallurgical sectioning Construction - concrete/masonry work; To be used with:; Portable grinder small diameter (2" - 4") Right angle grinder (4" - 9") Circular saw (6" - 8") High-speed gas/electric saw (12" - 16") Stationary machine large diameter (10" - 30") Chop saw (10" - 16") Arbor Size 1" Thickness 1/8" Type 1