Forum RPM and SPM Tachometer Generators are available in explosion-proof and non-explosion-proof models. Each generator has an output of 10 VAC @ 1, 000 RPM in either direction — clockwise or counterclockwise. 10 VAC @ 1, 000 RPM output. Explosion-proof model is listed by Underwriter's Laboratories (UL)for use in hazardous locations, Division 1, Group D (natural gas or the vapors from lacquer solvents, acetone, alcohols, and petroleum derivatives such as gasoline) and Class 2, Groups F and G. Easily mounted, with a direct connection to the pump pinion shaft by means of a flexible coupling or by a V-belt connection between the shaft and the generator pulley. A heavy-duty, oil-resistant electrical cord connects the generator to the RPM meter. Generator supplies all the power necessary for one or more Indicators — no outside power or batteries are required. Benefits Center-point mounted drums ensure optimum accuracy. Smooth, machine-grooved drum surface extends cable life. Heavy-duty, high-grade structural steel construction with tapered roller anti-friction bearings and heat-treated alloy shaft provides a super strong anchor with exceptional durability. Proof-testing to 150% of rated capacity ensures superior reliability. Durable bronze wireline clamp inserts provide tight cable grip without damage to the line. Easy to install and service.