I've googled and only jejamescycles have come up. I see Specialized offers them on its website, but there's no option to buy. Anyone know where else i can buy them?

Any Specialized dealer can get them in.

Yep – you do seem to have to actually go to a shop, but any spesh dealer should be able to get them quickly for you. Worked for me.

Although they do often run out for relatively long periods of time, particularly on helmets like the Decibel, which have been obsolete for a couple of years.

Try Specialized Customer Support – they're very helpful.