Manufactured from SS304L or SS316L, HV comes in 2, 4, and 6 in. port sizes and offers pilot operation. Latter enables automatic response for accurate regulation of system vacuum in precise 1:1 relationship with applied pilot vacuum set point. Only moving part, membrane diaphragm, directly creates seal against field of small orifices. Dynamic seals have no internal friction to overcome, enabling regulator to respond to changes in pressure nearly instantaneously.