Kyosho W5303-03 Big Bore Shock Seal (4)

Kyosho W5303-03 is a genuine four-pack of L-size shock seals for Kyosho's big bore dampers. These seals sit in the shock cap and cartridge, keeping oil in and dirt out while the shaft strokes through them thousands of times per run. They are the single most important consumable in a shock: as a seal hardens or nicks, the damper starts weeping oil, the oil level drops, and damping fades progressively through a race without any obvious warning until the car starts bottoming or feeling loose.

Replacing seals at every rebuild is standard practice for anyone running competitively, and at this price there is no reason to reuse old ones. These are direct factory replacements for Kyosho's big bore shock sets, fitting the Ultima RT5, RB5, RB6, SC, and DB along with the Lazer ZX-5 and ZX6 series. Package includes four seals, enough to service two shocks. Fit them with shock grease on assembly for smooth initial stroke.