When sourcing SC oil seals (Single Lip with Garter Spring), you must prioritize material compatibility and dimensional precision. The most common materials are NBR (Nitrile) for general oil resistance, FKM (Viton) for high-temperature and chemical resistance, and Silicone for extreme thermal ranges. Ensure the inner diameter (ID), outer diameter (OD), and width have a tolerance level meeting ISO 6194 or DIN 3760 standards to prevent leakage. Additionally, verify the spring material, typically carbon steel or stainless steel, to ensure it provides adequate radial force for the sealing lip.