The service kit for the 2020 SID B4 fork is part number 00.4318.025.215 (200 HOUR/1 YEAR SERVICE KIT (INCLUDES DUST SEALS, FOAM RINGS, O-RING SEALS, SEALHEADS) - SID SL (32MM) RL/RLC/XX/SELECT/SELECT+/ULTIMATE (2017-2020) B-GENERATION).
RockShox service kits and spare parts are best obtained through your local shop or dealer. See our dealer locator, below, to find a dealer near you. If no one is currently listed near you, then please search for local shops via your preferred web browser.
https://www.sram.com/en/dealer-locator
Manuals and additional information about RockShox and SRAM components can be found at our service site, linked below.
https://www.sram.com/en/service
Further questions?
Reach out to Rider Support by Asking A Question at the link below.
https://www.sram.com/en/rockshox/campaigns/rockshox-rider-support