1" Scope ring for weaver 3/8 dovetail or 10mm mount. It should mount for both sizes. I printed it out. Everything lines up great, minimal trimming to get corners true. I printed it @ .15 layer with 80% infill for strength. 5mm brim. PLA @ 200°C, make sure to print the clamp facing up on its side so the corners are crisper. It printed well with my settings. Good luck with yours. Feel free to redisign as you please,