Selection guidelines for SKF capping devices

Requirement	Shields	Non-contact seals	Low-friction seals		Contact seals
	Z	RZ	RSL	RST	RSH	RS1
Low friction	+++	+++	++	++	O	O
High speed	+++	+++	+++	+	O	O
Grease retention	O	+	+++	+++	+++	++
Dust exclusion	O	+	++	++	+++	+++
Water exclusion
static	–	–	O	+++	+++	++
dynamic	–	–	O	+	++	+
high pressure	–	–	O	O	+++	O

Symbols:
+++ = best
++ = very good
+ = good
O = fair
– = not recommended