Contact seals are made of oil and wear-resistant NBR or FKM and are reinforced with a sheet steel insert.
SKF single row deep groove ball bearings with a contact seal made of NBR on one or both sides are manufactured in four designs depending on the bearing:
Bearings in the 60, 62, and 63 series are equipped with RSH seals when D ≤ 25 mm.
Bearings in the 60, 62 and 63 series are equipped with RSH seals when 25 mm < D ≤ 52 mm.
Other bearings have RS1 seals, which seal against the inner ring shoulder
or against a recess in the inner ring side face . The difference is indicated by dimension d1 or d2 in the SKF bearing size chart