* A two-part device called a coupler lets you use
different decorating tips with the same bag of icing,
creating several designs with the same color and
consistency.
* A coupler (used in piping or plumbing) is a very short length
of pipe or tube,with a socket at one or both ends that allows two
pipes or tubes to be joined,welded(steel),brazed or soldered(copper,brass,etc.)
together.