Bezel and front cover with set point knobs and zero adjustment screw removed to expose Photohelic switch gage set point mechanism. Cover is clear polycarbonate plastic
Gage pointer and light shutter are mounted on helix and balancing counterweight. Shutter passes through slot in optical limit switch to expose phototransistors to integral infrared light source or mask them depending on applied pressure
Light shield effectively protects phototransistors from strong outside light sources yet allows free pointer movement. It also gives interior a clean finished look
Optical limit switches are used for reliability and long service life. Attached directly to set pointers, they are individually aligned to assure precise switching accuracy
Zero adjustment screw connects to screw in cover to adjust zero pressure reading