Slam Specialties' brand of high quality, high performance AirSprings has 4 sizes currently available: 5", 6", 7", and 8" diameters, and 3 pressure models of each (RE only for the 5"). All models are size and bolt pattern compatible with Firestone air springs. Size and bolt pattern is where the similarity ends. Slam Specialties' line of AirSprings are constructed with steel bead rings within specially-designed dual-end closure plates. All plates are permanently bonded (instead of clamped or crimped) to a technically advanced non-ballooning rubber bellows, making it virtually impossible for the plates to separate from the rubber - even unrestrained at maximum pressure. These technological advances in design provide an AirSpring that give improved performance in all areas. · Higher pressure: More than twice that of other manufactures. · More stroke: Useable from its absolute minimum to its absolute maximum · No Ballooning: All models are at their maximum diameter at zero pressure, and as their stroke increases the diameter decreases. · Faster Lift: 1/2" ports and no ballooning means all the force goes up, you get faster lift with lower pressure. · Internal bump stops: This standard feature keeps our AirSprings from self-destructing at zero pressure. · Stronger and stiffer: No more uncontrolled bouncing or swaying while driving. In fact, if installed properly, Slam Specialties' AirSprings will equal the ride of a luxury car. · Competition: Superior performance to hop higher measured in feet not inches, dance faster, and give more stroke to clear those 24s. Collapsed height- approx. 3". Extended height- approx. 8".