I have a 2" Optolong UHC in good condition. It's been a fun visual filter, excellent for nebula-watching. Very similar feel to a Baader UHC-S
It's been used gently - most of its working life has been spent in a filter wheel.
$80 including case. Postage is extra, or collect from Blaxland NSW
The filter specs:
https://www.optolong.com.au/uhc
Pic of the one for sale attached.