This is a suspension adjuster for LeaperKim (Veteran) Sherman-S, Patton, Lynx and future models, which uses Fastace suspension. I've made new design in order to put there a metal part for compression and rebound regulation, because a plastic one was easily broken by Semen An :)
Metal part size: 87.51 mm. I've used a piece of straightedge.

Flying Bear

Ghost 6

No

No

40%

You can place the metal part while printing in version 2.

Heat the metal piece and insert it into the hole in the part.