The Altimeter is a device used to measure the altitude of its position. There are various types of altimeters that use different methods to measure the altitude but the most popular ones are pressure altimeters. They are used by skydivers to know there exact vertical whereabouts. The casings are made out of plastic or even some light metals. The Altimeters display can be by a needle or have a digital display. They are mostly mounted to the hand of the person who is deploying the parachute. With minor accessories they can be mounted on other places that are easy to access on the harness.