Fox Internal Spool Valve Compressor Knob The Right Tool for a Clean Transfer Rebuild Rebuilding a Transfer Seatpost calls for precision at every step, and the spool valve assembly is where a rushed job shows up later. This dedicated service tool threads into the Shaft Lug during oil fill and bleed, letting you cycle the shaft and purge air from the Upper Post without losing control of the assembly. When you can see no new bubbles at the top of the oil column, you know the job is done right. For anyone doing regular Transfer Post service in-house, this knob belongs in your toolbox alongside the IFP height tools and the nitrogen fill setup. Features Dedicated Transfer Post fitment designed specifically for Fox Transfer Seatpost internal rebuild procedures Clockwise thread-in interface installs securely into the Shaft Lug for a controlled connection during oil fill and bleed Air purge function keeps the shaft assembly contained while you cycle the post to clear bubbles from the Upper Post oil column Fox part number 398-00-700 the correct OEM tool for Transfer internal rebuild per Fox technical documentation | Fox Racing Shox | Internal Spool Valve Compressor Knob Fox Racing Shox | Transfer, Race Face Turbine-R