... your order 4.connect rebar of HRB 335/400 This system contains one ZLB-09 taper thread machine and couplers, ... it can be used to connect rebar of HRB335/400,φ16mm-φ ... mechanical property of joint can reach grade II. The taper thread system has following advantages:1, Can be prepared ... not be rolled, with a right and left thread coupler.Certificate: