This clamping feed neck replaces the cheap plastic one that comes with the MR series markers. Remove the 3 screws that clamp the original feed neck in place replace with the clamping one and reinstall the screws about 4-5 minutes and you are done. Gives you a much more solid feel with the marker and holds the hopper much better than the plastic one ever did. I have an empire 2 loader and it has a very thick feed neck and it clamps in place with no issues. Works great
If you own an MR series marker this should be one of your first upgrades, A must have.