M-88 LIQUID PRISMATIC COMPASSLightweight and rugged aluminium alloy construction Prism sighting system for highest accuracy Liquid filled for rapid sighting Full day night use 5 Tritium lights Precision sapphire bearing Full MILSPEC build quality In service worldwide NSN: 6605 99 500 3822 The M 88 Dual Graduation with Mils and Degrees Liquid Prismatic Compass is built to the same exacting standards as the M 73, but is made largely from aluminium alloy, making it very lightweight.