The NPXX is unbalanced single-spring mechanical seal, relying on the spring to tighten on the shaft to follow the rotation.
According to the seal design type as follows
2.NP2X: Carbon/silicon carbide/tungsten carbide
3.NP3X: Silicon carbide/tungsten carbide + metal
Seat ring style with "A2","A3","A4","A6","A9"
eal Face Material: Silicon Carbide/Tungsten Carbide/Carbon