The Fingertip Pulse Oximeter, model 18700, is an oxygen monitor designed to measure oxygenation level in individuals with respiratory disabilities. Placed on a fingertip, this compact, lightweight unit measures oxyhemoglobin level and pulse rate. POWER: Uses 3.6V Lithium Batteries 0.5 d0uble-A batteries. Replacement batteries are available. The unit has automatic power-off and a low voltage indicator. WEIGHT: 50 grams including batteries. COLOR: Yellow.