Red o-rings used in homebrewing

[Jimmy]

Can anybody tell me the type of material used in the red o-rings used in homebrew equipment? I believe it's silicone, but is that all? I called Atlantic Hardchrome for some o-rings, and they tell me it's EPDM? I'm looking to get a bunch of non-black o-rings for work, but they need to be able to endure our weather. They aren't being used to seal anything, just to identify something as "inactive". I'm hoping for something that is UV protected, won't fade/crack.

[derek]

I don't know the material, but if the vendor is correct, then I can be pretty certain it isn't UV resistant. I've used EPDM for pond linings, and you order specifically UV stabilized material.

[chalmers]

It's Silicone according to McMaster.

Don't think I can copy/paste the Silicone O-ring link, but you get the idea.