PFERD POLINOX PNER unitized disc is used for end grinding on angle grinders. The unitized fleece is bonded to a glass woven base. The PNER discs are recommended for working larger areas on stainless steel (INOX) components. POLINOX PNER unitized discs achieve their best performance on variable-speed angle grinders at a cutting speed of about 6,900 SFPM. Ergonomically optimized products and power tools that contribute to greater safety and working comfort, and thus to health protection. Comfortable working with reduced vibration . Specification: Diameter x width (inches): 4-1/2 x 1/2; Arbor Hole: 5/8-11; Abrasive: Silicon Carbide; Grit: Fine; Grade: W; Density: Soft; Spec.: 2SF; Recom. RPM: 6000; Max. RPM: 10000.