Thanks! I really like it because you can adjust zero by hand. No screwdriver needed.
Its this one here
https://www.bullseyecountrysport.co.uk/tokyo-marui-new-pro-sight-high-precision-dot-type-scope-airsoft-no122-178220-39621-p.asp
I've also popped a little 30mm polycarbonate disc I got from ebay under the cover, to stop bb impacts.