The K-Tech ORSS-2, Air2Spring system replaces the original air spring chamber in the WP 43AER forks. The simple design allows you to remove the original air spring system and replace it with a more conventional spring system. The ORSS-2 features a new a hydraulic bottoming device which protects the rider on hard landings and requires no machining to install. External spring preload adjustment Direct replacement (No machining required) Hydraulic bottoming device Hard chrome piston rod Aircraft grade aluminium parts **Note: The ORSS system requires a 385-580- series spring. Inner Diameter (mm) 20.00 Length (mm) 849.00 Outer Diameter (mm) 10.00 Preload (mm) 10 Oil / Air Gap (left) 250cc Oil / Air Gap (right) 363cc Oil / Air Gap 250 P/N: 122-018-155-085 FITMENT: 2018-2025 KTM 85 SX 2018-2025 Husqvarna TC85 2021-2025 Gas Gas MC 85 Please ensure fitment prior to purchase. Item will come in original packaging. If you have questions, please contact the seller. Not responsible for improper or ill fitment due to incorrect year, make & model given by buyer upon purchase.