An adapter for using the very old L39 or M39×26tpi Leica rangefinder lenses on a Sony E-mount camera. Does not have M39 threads just a gentle cone to screw the lens into. It's up to you to make sure the lens is on straight and any controls are where you want them.
Disclaimer: Use at your own risk. This is a freebie from the internet. No warranty. 3D printed lens adapters are very imperfect. Do not trust this to hold your expensive vintage Leica lens. Don't trust it to hold your grandfather's Leica lens. It may look precise but there is a lot of guesswork and just eyeballing it that went into the construction of this.
The all metal adapters are inexpensive and more accurate. This is to try out a lens in a carpeted area while that adapter is in the mail. This is to play with cheap Russian lenses that are L39 mount.
Doesn't focus at infinity? It might not quite do it for you. Try closing the lens up to ƒ/8 - that's pretty good for landscape.
I would try not to use supports.