... huge selection3. factory directly4. core bit for concrete, etcdrill bit for stone:Outer Diameter Seg H(mm)Working ... 38358601.57408601.97508602.17558602.36608602.76708602.9575860core bit for concreteOuter DiameterWorking Length (mm)inch"mm0.8"203601 ... All these products have reached international advanced standard, which extensively used for cutting, grinding or polishing stones, refractory, porcelain, ...