The 2-1/2" round brass enclosure is used for many standard Navy "Symbol" items, but is not covered by a military specification. The basic enclosure design is based on the NavShips drawing 9-S-73754. We offer it as an empty enclosure with a blank cover and a blank nameplate so it can be used as a junction box, terminal box, switch box or wherever you need a small submersible (15 feet) brass enclosure. It mounts with (2) 1/4-20 bolts or screws and it has 2 sides that are flat for cable entry. This is the smallest submersible brass enclosure that we offer and the least expensive. It is also available in aluminum if weight savings is of benefit. Our part number 404900-101.