Barska Binocular Tripod Adapter Red Dot

Adapted some existing models to fit the Barska Binocular Tripod Adapter to hold a finder scope or red dot sight. https://www.amazon.com/gp/product/B000BYH8EQ

I've also seen this called an RSR or reflexive sight rail. I use a Celestron 25x70 with this setup and it works great.

Its a snug fit so it doesn't wobble, but it doesn't require any additional hardware unless you want to put M3 screws in the holes to hold the red sight in place.