Our diamond stone core drill bits are used for drilling all kinds of stones, refractory materials, etc. diamond stone core drill bits for granite, marble,refractory materials,etc1, Used for : all kinds of stones , such as ... : 8mm--200mm.M14,5/8"-11 Connection3,Feture:fast cutting and long life4,MOQ:50pcs5,Payment : L/C6,Packing : White carton7 ...