I needed a way of mounting a TTartisan light meter to my m645 for the more picky film thus, this mount was born. It was able to survive a multi week trip to Germany and Italy with no issues ,however, you do sacrifice use of the tripod mount. I printed it in PETG but other filaments such as PLA should work fine as well. The screw I used to hold the mount to the body is a ¼-20 x ¾ Flat Head Cap Screw similar to this one at Lowes https://www.lowes.com/pd/Hillman-1-4-in-20-x-3-4-in-Allen-Drive-Cap-Screws-4-Count/50088794