Enclave crate (Fallout 3)

Enclave Crates are used for storage of various items, including Energy Cells, Microfusion Cells, Missiles, Flamer Fuel, Plasma Mines, Pulse Mines, and Stealth Boys.

Locations
Almost all of the Enclave Auxiliary Bases deployed into the Capital Wasteland will contain one of these crates, and usually more. They can also be found in Raven Rock while escaping in The American Dream.