The ultimate upgrade for anyone that's serious about towing is a set of rear air springs or helper springs. These awesome systems and kits eliminate rear-end sag when towing extremely heavy loads and keep your truck leveled to avoid porpoising, headlight misalignment, and adverse handling when your Super Duty's rear suspension is weighed down by whatever you're towing or hauling around. A few of these systems can level out 5,000 lbs. of total load and come high-tech air systems that can automatically change the air springs pressures with the push of the button. We have air bag and helper spring kits for just about any application or budget just waiting to jump onto your truck. Ford Super Duty Fitments: 2011, 2012, 2013, 2014, 2015, 2016 Ford F250 & F350 Submodel Fitments: FX4, King Ranch, Platinum, Lariat, XLT, XL Some Exceptions apply, please see individual product pages for specific fitments.