advantage: 1. good balance 2. sharp fast grinding 3. soft bond for hard material 4. coorespondent formulaes for exact stone Usage:1. For stones, such as granite, marble, natural and artificial stones, etc.2. For grinding, leveling, shaping and polishing stone surface, corners,edges and angles. Other sizes and types as below:- Size(inch)3, 4, 5, 6, 7, 8, 9TypeSingle Row, Double Row, Turbo Row, ...