Shank size is 25*159mm, and shank end drill rod end connect bit with thread way. Normally R22,R25,R32 for small hole. We manufacture shank end rods in the following threads: R22, R23, R25, R28, R32 mainly focus the stone quarrying such as granite, marble, limestone, sand stone quarries drilling, diameter of hole range from 32mm-64mm at most.