Rust, IIRC they are about 20 quid, I guess about a fiver for the adapter. Not sure who does them, I guess any RWS agent - maybe BAR or JSR ?

Not massively effective on 12 FP PCPs, but on my 6FP PCP (Falcon) pistol, and on springers (with their relatively low air volume), they are very effective for their small size...

You want me to keep my eyes open ? <img src="http://jsramsbottom.co.uk/bbs/e/icon_wink.gif" alt="Wink" width="15" height="15"><!--graemlin:-->