Standard couplers: these white couplers are 3 cm/ 1.2 inch long, and their base' diameters are 2.5 cm/ 1 inch, fit for standard-size icing nozzlesUsable range: the standard coupler fits all decorating bags and standard-size tips, helps you change piping tips without unnecessarily wasting bags or frostingSimple to use: cut a tiny hole in the bag corner, insert this plastic coupler, then attach the tip and screw on the ring, after done, remove the tip and coupler, wash them cleanDurable and practical: the pipe tip couplers are made of quality plastic, with sturdy construction, make you decorate cake and cookie conveniently and quicklyQuantity: 12 x cake decorating couplers, enough for different usages, you can change similar sized tubes without emptying the contents of the decorating bag