Prodelin C band polariser for use in 1.8m or 2.4m antennas with O ring and bolts/nuts.
Specification and drawings here:
https://www.satsig.net/forum-archive/prodelin-polariser/prodelin-c-band-circular-polariser-feed.pdf
If interested, please email me eric@satsig.net reference 20:12 3Mar2021 and I will forward your email to the seller.