Machined out of aerospace spec billet alluminium and then anodised in either gold or black and then laser etched & machined to give the finished product that you see here. We have made the vent valve pipe to the same diameter as the standard rubber, so if you want to fit a flush fit breather they may need a trim, as as with a brand new plastic standard cap it is a tight fit. As the different flush breathers are tighter than others, Future trial breathers for example are slightly smaller in diameter than our own H&D vent breathers.  These are supplied with the genuine seals kits also, simply open the pack, remove the old plastic top and fit, bingo. 
 
Fitment- 2005 - 2019.
Will not fit the 2020 models!