These complete air spring cartridges for Ohlins forks feature their three-chamber air spring system with two externally adjustable springs: adjust the main spring by adding air into the top valve, and control the progressivity by changing pressure on the bottom of the fork of the ramp-up chamber. The third chamber is the negative spring, which can futher be customized by removing or adding up to two volume spacers.Complete Ohlins 180mm air spring cartridge for the DH38 fork ONLYFeatures the three-chamber air spring system with two externally adjustable springs: adjust the main spring by adding air into the top valve, and control the progressivity by changing pressure on the bottom of the fork of the ramp-up chamberThe third chamber is the negative spring, which can futher be customized by removing or adding up to two volume spacers (requires dissassembly)Cartridge ships with one negative volume spacer installedIncludes a new bash cap to prevent damage to the air valve on the bottomCartridge design allows easy travel change without removing the fork and allows the fork to be swapped between a coil spring setup Ohlins Complete Air Spring Cartridge Assembly Air Springs & Parts UPC: 840153640735