There called 'Armourdillo Downtube Protectors', they wrap around your downtube and have protective rods runing through it to stop dents to your downtube. Heres a review of them. I brought mine off of Ebay, brand new, but that was 6 months ago. Unfortunatly they've now gone in to doing SkateBoard Decks - Here's the site. Me and Ozzy were talking about this the other day. We said someone (ie. TartyBikes) should make a copy with 'TartyBikes' printed down the side, they could even do them in different colours to match your setup! - I'd by one (in green ) Would you buy one?