The Monoprice Maker Select V2 comes with a spool holder that is too short for most spools. This design, along with the existing spool holder components, allows for full sized spools to easily be used and solves some design issue found in other spool holder designs. The Wanhao Duplicator i3, may also make use of this mod.

Inspired from Michael Miller's design, https://www.myminifactory.com/object/maker-select-wanhao-duplicator-i3-spool-holder-adapter-23221.

The design offers a few key features, I haven't found in existing designs.

1. It is longer, so it can fit normal spools with room to spare.
2. The radius that sits against the spool is significantly wider, better fitting the contour of most spools, allowing smoother spool rotation.
3. A "key" can be inserted so that it doesn't slip out over time.

To use the design, rotate the original spool holder shipped with your machine 180 degrees, so the square channel is facing upward. Take this printed design, and slide it through the original spool holder, with the rounded side facing upward. Take the small key piece and insert it into the spool holder print so that it can no longer slide freely.