Linear rail block stoppers

I converted my X and Y axes to linear rails, and needed stoppers to prevent the blocks from passing the edges of the rails, potentially losing dozens of tiny bearing balls. I whipped these up real quick, figured I'd share them here in case they're of use to anyone else.

They're 20mm wide, so they fit nicely on the 2020 extrusion, and they're wide+high enough to stop the rail slider block from getting past.

There are two versions:

The regular STL is designed for M4 screw and T-nut, but M3 may also work. You can see this printed in orange PETG in one of the photos.

The small STL is designed for M3 screw and T-nut, and they're a lot narrower. Use this if you have very limited space (such as at the ends of my X rail). You can see this printed in green PLA in one of the photos.