Diopter adapter for Leica 21mm finder

Designed an diopter adapter to the Leica 21mm Brightline metal finder. Used a Mamiya RB/RZ +3 diopter lens as I had one around. It has a good size and they sit in a soft plastic frame for easy removal. Printed in Carbon fiber PETG 0.1 mm layer hight. This way the frameline is nicely visible. Designed as tight fit. Can also be secured with M1.5 mm screw from the bottom.