I am looking for a supplier of black plastic caps to cover hex bolt heads - 1/4" to 9/16".

I've tried searching the internet and I have found some suppliers, but I was unable to locate the exact part.

I've seen some nice covers on some exercise equipment at the gym.

Try Caplugs (http://www.caplugs.com). We buy bolt covers and paint caps from them. Large selection, reasonable prices.

http://www.mcmaster.com/ has some as well. They are probably the easiest supplier I have ever dealt with as well, this is EVEN across border for me!

Thank you guys, I've found what I needed at Caplugs.