Clear plastic face is highly resistant to breakage. Provides undistorted viewing of pointer and scale. Precision litho-printed scale is accurate and easy to read. Red tipped pointer of heat treated aluminum tubing is easy to see. It is rigidly mounted on helix shaft.
Pointer stops of molded rubber prevent pointer over-travel without damage.
Motion damped with high viscosity silicone fluid. Zero adjustment screw is conveniently located in plastic cover, accessible without removing cover. Helix is precision milled from an alloy of high magnetic permeability, deburred and annealed in a hydrogen atmosphere for best. Mounted in jeweled bearings, it turns freely to align with magnetic field of magnet to transmit pressure indication. Alnico magnet mounted at one end of range spring rotates helix without mechanical linkages.