Houper HOU-MDT836100 metal detector rocket has many uses in entrances and public places. It prevents the hot and cold weapons such as guns and knives to be carried into such places. Damp-proof sensitivity adjusting feature of Gates manual metal detector rocket allows the user to adjust the sensitivity to humidity. If the battery drop down to a low voltage, it may show some errors, and it may not function properly. With an independent low voltage battery system, the device can function properly even when the battery voltage drops to a low level. Another important feature of Gates manual metal detector rocket is its shield. This means that the device has a protective cover that prevents electromagnetic interference and other electronic noise.