the IRP (Intuative Race Products) frame sliders are pretty nice. And a great thing about them is that you can purchase the OPTIONAL end-caps for about $8.00.
Oh, and make sure to place a bit adhesive to the end-caps, EVEN if they fit really tight going on.
I took my bike to the dealer to get serviced, and upon picking-up my bike, noticed that my left end-cap was gone. (So I accused them of losing it - which was bad). But since I could not PROOVE that the cap was there when I left my bike to be serviced, I couldn't do anything. So I ordered a second set.
Then I noticed two days later that the left end-cap was gone again. (Geesh, the SECOND ONE)!! And I thought to myself..."Dog-gone squids, why'de they only snatch ONE end-cap while I'm parked downtown"? (So I replaced it the THIRD TIME - with the last one). But this time, while I was driving, I just happened to hear a slight "tinkle-tinkle," and looked-down in time to see it rolling away!! Blahhhhhh!!!
You see, because they went on so TIGHT (I used a soft-faced, rubber-head hammer), that I thought people were stealing it. I'm telling you, they were on TIGHT!!
So I pulled-over, found the little rolling bugger, and placed a strong adhesive on BOTH of them this time out. And since then, NO PROBLEMO'S!!