Summary

If you have sliding windows that travel in a channel approx 1.30" wide, chances you will have "stops" at the end to prevent the window from hitting the frame when fully opened. Our vinyl windows have PVC window stops. I made these printable stops that are stiffer than the PVC version, so any heat through the window won't cause them to fall or snap out easily. If you need to take them out, stick a screwdriver through the large hole and angle it out. But they should be easy to pop off.

You can adjust the length in your slicer. In PrusaSlicer's lower right corner ("object manipulations"), unlock the scale factor / size, then adjust your desired length along the Z axis.

PETG will make it a bit more temperature / UV resistant than PLA.