Single seal
Unbalanced
Single spring
Bi-directional
Elastomer diaphragm

Equivalent to John Crane type 21/521, PAC-seal type 21, US Seal type C
Seal faces: Carbon graphite(resin-impreg), silicon carbide, tungsten carbide
Stationary seats: Silicon carbide, alumina ceramic, Ni-resist, tungsten carbide
Bellows: Neoprene, NBR, FPM, EPDM
Springs, other matel components: AISI 304, 316, 316Ti
Secondary seals: Neoprene, NBR, FPM, EPDM.