The Fox O-Ring (-312) is a replacement static seal, part number 029-03-312-A, sized to AS568 dash -312 with a .210" cross section and a .600" inside diameter. Because it seals parts that do not move against each other, it suits the static seal locations found during a damper rebuild. Match the part number to the seal you are replacing before ordering, since an O-ring of the wrong size will not seat or seal properly.
A correctly sized Fox O-ring is worth choosing over an unlabeled bulk O-ring of uncertain dimensions. Using the exact dash size and the manufacturer's part number removes guesswork during a rebuild, and the part costs very little, so replacing it at every service is an inexpensive way to prevent oil weeping and leaks. Keep a spare on hand for fork and shock maintenance intervals. Searches for Fox -312 O-ring, Fox 029-03-312-A, AS568-312 .210 cross section, and Fox static shock seal replacement will lead you to this exact part. Lubricate the O-ring with the fluid specified for your damper before installation, and confirm the correct groove and application against the manufacturer's service documentation for your model.
