DISC 8" PSA 60-GRIT (50/BOX)|1950 SERIES|sia Abrasives 1950 siaspeed PSA discs are versatile all-around discs with extremely long lifetime, very high stock removal rates and excellent finish, and low abrasive consumption. Due to the open coating in the 220-600 grit range there is minimal clogging. The 40-80 grit range contains a performance-enhancing grit mix with ceramic corundum. siaspeed 1950 PSA discs are typically used for keying of polyester and composites, feathering edges, and flattening body filler and primer filler.