Here's a fun DIY / product idea.  A Christmas keychain "pipe helper" to help determine  maker pipe compatibility.  Insert any found pipe inside the keychain, and a slot would tell you how many shims/bands are needed.  It'd be a 3D printed half-cone or cone-shaped "tree" with little slots depicting the number of bands/shims needed.  I'm not sure if I got my measurements correct, but regardless, you get the point.  Merry Christmas everybody!