It is a concrete blockhouse, semi-circular in shape with a diameter of about 6 metres (20 ft).

Its walls are 1.22 metres (4.0 ft) thick with four firing ports large enough to accommodate 20mm cannons, originally equipped with steel sliding shutters.

A steel door 25 millimetres (0.98 in) thick provides access to the structure at the rear, sheltered by a concrete wall and covered defensively by a machine gun port.

The blockhouse is located near the center of what is locally called Big Agingan Beach (Unai Dankulo Agingan), on the south coast of the island, about 20 metres (66 ft) from the shore.

This article about a property in the Northern Mariana Islands on the National Register of Historic Places is a stub.