application should be self-explanatory...

cylinder (green): outer diameter: 70mm inner diameter: 55mm height: 62.5mm max. useable height: 40mm min. useable height: 13mm

ring (blue): inner diameter: 30mm (or 35mm) height: 10mm

additionally needed: 2x M4x10 to secure the ring in the cylinder something like a pin (I thought of a wodden skewer) with a diameter 4 mm to assemble the ring

(untested design)