Explosion-proof, UL & CSA Listed for Class I, Groups B, C & D and Class II, Groups E, F & G. The H2 is designed for sequencing two different actions as pressure of a liquid or gas increases or decreases. The patented design consists of two concentric pistons operated by a single diaphragm with one pressure chamber. Each piston actuates a separate switch independent of the other. The switches may be adjusted to operate together, at opposite ends of the range or at two intermediate set points. The threaded top is removed to field adjust or service switches without disturbing electrical or pressure connections. The Duotect® switch is explosion-proof and weatherproof. It can be mounted in any position and is not affected by vibration.