These parts represent the exposed warhead of the Bliss-Leavitt Mk.8 torpedo fired from US Navy PT boats, among other USN and Royal Navy Lend-Lease-procured vessels, during World War Two. When loaded into the torpedo tube, the Mk.8's domed warhead was exposed. A good reference for PT boats can be found on NavSource (click here).
precisely scaled, outer diameter of exactly 21 scale inches
triangular end-cap, a plate installed in the field to prevent the torpedo from falling out of the tube in rough seas (install the warhead so that one of the plate's corners points up)
This product is also available in several finishes of durable, real stainless steel, recommended for a true metallic appearance and rugged radio control operation.
These parts are not 3D-printed copy of any plastic model kit's parts.