Description Mark 14 Mod 15 Gun Sight for 40mm gun mount. S/N 56406. Made by Sperry Gyroscope Co. Tested and passed May 24,1945. Chipped control knobs. Broken Cannon connector. The Mod 15 gun sight was used with power driven single 40mm mounts Mk 4 Mod 3, where it is mounted on its side to a support casting attached to the gun housing. The Mod 15 gun sight has a maximum range of 3,200 yards, like the Mod 8 gun sight used with the Mk 51 director. It is otherwise similar to the other mods designed for use with 20mm guns. Includes a lamp with dimmer rheostat, reticle block and collimating lens, elevation gyro and transparent elevation mirror with damper, traverse gyro and mirror with damper, range adjust gear train, super-elevation correction weights, neutral density light filter, and air pressure regulator. This gun sight is used with a power unit that provides clean, dry air for the gyros, and switched electrical power for the oil heater and 10 volt reticle lamp.