Remind: The velcro pad holder’s arbor is 5/8-11 female thread. Remind: Pad Holder’s max velocity / capacity is 5000 RPM. Please DO NOT use it with high speed grinder or polisher. (a) 45 Pieces of 4 Diamond Premium Grade wet DRY wet dry use. DRY USE RECOMMENDED Polishing Pad for granite marble concrete. 9 X Grit 50 100 200 400. 3 X Grit 800 1500 3000. (b) 8 Pieces of 4 Diamond Double Row Grinding Cup Wheel for concrete stone travertine surface sanding smoothing. Cup wheel is random color: Red or Blue or Black. (c) 1 Piece of (5/8″-11 Female Thread arbor) 4″ Velcro Backer/Pad Holder. Velcro backer’s max capacity / velocity is 5000RPM. Please don’t use it with high speed grinder / polisher. (d) 1 Set of Lock ring Nut and wrench (fits 5/8-11 Thread grinder or polisher). Pad: 2.3mm thickness. Recommend 2500 – 5000 rpm.