Large Cake Decorating Coupler Set - This Ateco 3-piece medium plastic coupler allows you to interchange medium-sized piping tips with absolute ease! Even though all reusable bags can accept small decorating tips without a coupler, this convenient item enables you to swap out medium-sized piping tips without having to empty the contents of your decorating bag, which saves you time and labor. That said, to use this coupler properly, simply trim your reusable bag before use! However, since canvas bags with a sewed seam cannot be trimmed, they are not compatible with this item. Although this coupler works best with medium-sized piping tips that have a 3/4" bottom diameter, this item's 7/8" coupler ring can accommodate 3/16", 1/4", and 5/16" pastry tubes, as well as Ateco's 231 large bismark tube, while 1" coupler ring can hold 3/8", 7/16", and 1/2" pastry tubes. In addition, ridged edges on the ring allow you to easily assemble the coupler to the base with minimal effort. Ideal for bakeries, cake decorators, coffee shops, and anywhere else you need to decorate baked goods, this plastic coupler will get the job done!