Ball Washer Ball washer is compatible with domed plate in the rock bolt system ,it can provides up to 180 angle of tilt, has ‘user friendly’ rounded corners ,that can make the face of rock and the plate and spherical washer connect tightly whatever angle does rock face have . Feature : It can increase the bearing strength of domed plate It has user friendly rounded corners, that can make the instalation simple. In the rough and inclined rock face ,it can adjust the angle,make sure the face between plate and rock connect tightly .