The performance of sealing is vital to the cleanliness of the lubricant and the overall service life of the bearing arrangement. Integral bearing seals must be able to keep contaminants out and lubricant in the bearing cavity.

● Inner ring seal groove types

V-groove	L-groove
HCH bearings give priority to adopt “V” type seal groove, which have better dustproof ability	Other bearings for electric power tools adopt “L” type seal groove, which have general dustproof effect

●Shield and seals

Type, code No.	Shielded type	Sealed type
	Non-contact type	Non-contact type	Contact type	Tight sealing type
HCH	ZZ	2RZ	2RS	2RS1
Construction
Torque	Low	Low	Medium	Higher torque than 2RS
Dust proofing	Very good	Better than ZZ-type	Good	Excellent
Water proofing	Poor	Poor	Good	Excellent
High speed capacity	Same as open type	Same as open type	Better than 2RS1	Good