Why we build it in PVC

We standardised this cap on PVC (polyvinyl chloride) rather than natural rubber, for reasons that matter to a buyer running thousands of these in the field.

PVC resists oil, grease, and a wide range of industrial chemicals without swelling or perishing, so the cap does not degrade from contact with the very lubricant it protects. It also holds its colour and flexibility across long outdoor exposure, where natural rubber tends to crack and stiffen with age and UV.

It moulds to a tighter, more consistent tolerance at high volume, and holds a high-visibility red finish permanently, so a missing cap is obvious on inspection. The result costs less to manufacture at scale without giving up sealing performance, which is why it has become our flagship line.