Grinding wheels for metal, tested in German EN12413 standard and fit RoHS and PAHs. Features: 1) Dimensions: a) 4" x 1/4" x 5/8" (100 x 6 x 16mm) b) 4-1/2" x 1/4" x 7/8" (115 x 6 x 22.2mm) c) 5" x 1/4" x 7/8" (125 x 6 x 22.2mm) d) 9" x 1/4" x 7/8" (230 x 6 x 22.2mm) 2) Product specification: A24RBF 80m/s, the meaning of A24 RBF 80m a) A24: aluminum oxide materials grit 24 b) R: harness grade c) B: combined material 'resin' d) F: fiber glass reinforced e) 80m/s: rpm, means meter per second, rotary speed 3) Characteristics and applications of discs: a) Applications: general purpose disc for stone working, such as marble,glass, non-ferrous and soft metal b) Nets in bottom side of the disc c) Characteristics: standard quality, made of normal grade corundum,medium hard bond, flat type black color, high speed, 4) Operation description: a) We must operate the discs correctly, or they will make dangerous to us. The discs should be mounted with the flanges very tightly. The workers should operate the discs with safeguard b) The discs are for metal or stone applications, and we should use them for right applications c) To use suitable hand tools for operation of different sizes discs, with different ampere currents