Hella Battery Master Switch - For interrupting circuit (prevents theft and short-circuit during absence). Tin plated contacts. Flush or surface mount. Seawater resistant. Removable key. U.L. listed. Max. load: 1000A @ 12V, 500A @ 24V, for 10 seconds. Comes with a spare key. Dimensions: 2-5/8" height from panel, 2-1/4" diameter, 1-1/2" depth behind panel, 7/8" diameter hole in panel required.