Gas Props for Camper Shells, Tonneau Covers, and Other Uses TRUCK UPFITTERS CAMPER SHELL & TONNEAU COVER GAS PROPS 10″ to 11″ Props (pictures not to scale) Compatible ONLY with RKI Aluminum Toolboxes (11.4″ extended, 8.4″ compressed 70 lbs of pressure each) for Standard Width Single Lid ONLY (NOT FOR DOUBLE LID/WIDE TOOLBOXES) 12″ to 14″ Props (pictures not to scale) 15″ to 18″ props (pictures not to scale) 20″ to 30″ props (pictures not to scale) fits Undercover Tonneau Covers ONLY. (Except Ford SportTrac Undercover) Compatible with some (but not all) Snuglid SL and F2 Shortbed and Extrashort bed (5.5-6.5′) Compatible with some (but not all) Snuglid SL and F2 Long bed models (8.0′-8.5′) Compatible with some (but not all) Snuglid SL and F2 Long bed models (8.0′-8.5′) Compatible with some (but not all) Snuglid SL and F2 Long bed models (8.0′-8.5′)