Hydrogen peroxide is described as a valuable non-irritating and non-poisonous antiseptic. It effervesces in the presence of pus due to the liberation of oxygen. Usual strength 10 volumes, i.e. it contains ten times its volume of available oxygen.
Heat pump (as used in geothermal industry) in which the refrigerant exchanges heat in a heat exchanger with a fluid circulating through an earth connection medium - ground or ground water. The fluid is contained in a variety of loop/pipes configurations depending on the temperature of the ground and the ground area available. Loops may be installed horizontally or vertically in the ground or submersed in a body of water.
Hairspring is defined ad a fine spiral spring that regulates the movement of the balance wheel in a timepiece. Also known as balance spring, this is the small spiral spring that is attached to the balance wheel, the quality of which can affect the regularity and accuracy of a movement.
A Handheld vacuum is a machine which is portable and sometimes cordless which make them ideal for cleaning small areas like the car. In addition to upright vacuums, it is good to use handheld vacuums because they can clean areas which an upright can not clean because they are too large.