The INSTA-FIT ANTI-SIPHON for Peterbilt from HD Fleet Fuel Caps is the only ANTI-SIPHON that is designed to work seamlessly with factory lever style Peterbilt fuel caps. While keeping you original factory lever style fuel cap, fuel saving anti-siphons,  Insta-Fit Anti-anti-siphons help provide a tighter seal and prevents  leaky fuel caps.  Easy to install in 10 seconds, with no tools, this anti-siphon system solution simply presses and locks into the filler neck. Engineered with welded polished stainless steel rings, it delivers fast fill-ups with no frothing, splash-back or pump interruptions.
NO OTHERS ARE AVAILABLE and Patents Pending are sure to issue!