We've taken our decades of experience in Early Bronco suspensions and produced our progressive rate coil springs to be the best available, period! Several independent tests by Bronco owners have shown our springs not only provide a higher degree of ride quality, but out travel and outlast any other coil on the market. We realize that every Bronco owner uses their vehicle in a different way.We addressed this by creating a four stage progressive rate spring that provides excellent on road ride and handling, as well as jaw dropping suspension travel that lasts. Having a spring that lasts is extremely important since most people don't want to be buying springs every couple years. We use our own proprietary version of spring steel to provide a spring that does not sag,even after thousands of miles of testing. Our progressive coil rate gradually increases as the coil compresses.The upper wraps are softer for a more comfortable street ride; the middle rates are a bit firmer to handle bumps and dips without jarring; and the last few wraps are a higher rate so that they control the up travel to prevent bottoming out. The progressive nature of the spring also allows for better and more predictable handling by helping keep the vehicle flatter in the corners and limiting body lean. Our Broncos are our daily drivers and our play vehicles. We've been there and done that, so you can rest assured that no matter what you want to do with your vehicle, our suspension will take you there and back in comfort. All coils are blue powder coated for durability. NOTE: Due to the longer coil, a coil spring compressor may be needed in order to make installation easier on some vehicles.