Standard Model:used in the occasion for connecting the steel bar in normal situation Different Diameter Model:used for connecting the steel bar in different diameters Flared Model:used for the steel bar which was hard to match Positive And Negative Screw Thread Model:used in the occasion when the steel bar in the two sides both can not be turned but the lengths can be adjusted. Locking Nut Model:used when the steel bar can not be turned, then it turns the splicing coupler to join the steel bar and then lock the splicing coupler with the locking nut.