The NSN 4730-01-263-7151 is a Straight Pipe-to-Tube Adapter. It is designed to join standard pipe or pipe fittings to tube or tube fittings in a perfectly straight line.
 
Technical Characteristics
Material: Copper alloy (overall construction).
Connection End 1: Standard pipe threads or an unthreaded end for pipe accommodation.
Connection End 2: Machine threads (straight threads specifically for tube series) or an unthreaded end for tube accommodation.
Manufacturer Data: Associated with AM General LLC (CAGE 34623).
Part Numbers: 12354854 and 12354854-1
 
Vehicle Applications
This specific adapter is a recognized maintenance part for the M113 family of armored personnel carriers and its variants:
M113A3: Armored Personnel Carrier.
M577A3: Command Post Carrier.
M1064A3: 120-mm Self-Propelled Mortar Carrier.
M1068A3: Standardized Integrated Command Post System (SICPS) Carrier.
M58: Mechanized Smoke Obscurant Chassis. [1]
Official technical drawings for this part are typically found in military manuals such as TM 9-2350-277-24P.