This unflown 100 pound thrust hypergolic Reaction Control System or "RCS" engine, was supplied by the Marquardt Company on Van Nuys, California in the late 1970's.
Clustered in groups of four, there were sixteen thrusters on the Lunar Module. They were integral to rendezvous and docking manoeuvers in lunar orbit and essential for attitude control during lunar landing.
Used extensively throughout the space program I was informed that this display piece was from the Apollo program were they were used as directional thrusters on the Apollo Service and Lunar Modules.
The engine featured on The BBC's Antiques Roadshow filmed in Port Sunlight on The Wirral and first broadcast on October 21st, 2012.