12 × 37 × 12 mm. deep groove ball bearing has contact rubber seals on both sides, helping retain lubricant and protect the raceways against contamination and moisture.
20 × 32 × 7 mm. deep groove ball bearing has contact rubber seals on both sides, helping retain lubricant and protect the raceways against contamination and moisture.
35 × 80 × 21 mm. deep groove ball bearing has a non-contact metal shield on one side. The shield limits the ingress of larger contaminants and lubricant loss while retaining low friction; the opposite side remains open.