After designing my first spool holder, I wasn't very impressed. I decided to redesign it to use a 1/2 standard American PVC pipe so I could make it any width I wanted on a round surface so there is no resistance when the spool turns. I designed it to hang from a wire shelf. This is awesome. VIRTUALLY ANY SPOOL CAN HANG FROM A SET OF THESE! The Plug is designed so that if its a little too big it will give in the middle for a tight fit or if its a tad too small you can put a screw in it to make it stretch. Simple. pop the hanger and cap on one end of the PVC, feed through the spool then pop the hanger and cap on the other end! BOOM! you got a kick butt filament holder that can be any size you want!