SS-5, 5.5” SLAM SPECIALTIES 1/2” PORT, 250 PSI40% lighter than the RE series, 250psi rating, and an additional 1" more stroke give this bag more of what made the RE's great! Technical Specs:250psi Pressure ratingCollapses to 2.7"Extends to 8.625"Integrated Bump Stops for Strength and Durability6061-T6 Custom CNC aluminum inserts and port meet and exceed thread strength of the RE series(1) 1/2" NPT Port(2) 3/8"-16 Mounting Holes in the Top Plate(3) 3/8"-16 Mounting Holes in the Bottom PlateForce to Collapse to 2.7": 50 lbs*Slam Specialties do not recommend running the SS with the RE or HE.  The bag has more stroke, and is of a different profile, ride characteristics will be affected if different styles of bags are mixed. They recommend running all models of the bags in pairs.  The same model on the front or rear of the vehicle.