Bicycle inner tube for me. I change it about every 5+ years. Also if you wash your truck or it gets rained on, consider punching a drain hole at the bottom of the cover at the middle portion where it is the lowest, in case water get's in.
Here’s a pic of the drain hole
Craig
My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear My truck ....... Respect The Rust If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.