Aluminum, Plastic, Steel, Copper
An Apollo Command Module (Block II) Earth Landing Sequence Controller ELSC, manufactured by Northrup Ventura (the same company also developed the rest of the CM Earth Landing System including the 83.5 foot diameter parachutes, an example of which is include the collection and detailed in a subsequent entry on this site). 2 of these units were installed for redundancy in the spacecraft’s Forward Equipment Bay. The sequencer, was a subsystem of and employed by the Sequential Events Control System (SECS) to initiate deployment of the Command Modules Apex Cover (forward heat shield), the two 16.5 foot diameter conical-ribbon stabilization Drogues, three 7.2 foot ring-slot Pilot which extracted the three 83.5 foot white and orange stripped Main parachutes (the Drogue and Pilot were mortar deployed).
The front interface panel of the ELSC includes a Static Air Port on the lower right of the panel which served as the input for the 24,000 and 10,000 foot baroswitches; their closure armed and subsequently triggered initiation of the 3 mortar deployed pilot parachutes to extract the main canopies