It is designed for indoor/outdoor use and is easy to read with its large back-lighted LCD display. Power is supplied by a 9V battery with 150-200 hours of life. Designed for use by electricians, technicians, and serviceman who require an instrument that is accurate, reliable, and always ready for use. Its rugged boot gives a snug feeling when held. Daily users will appreciate the extra care taken with the test leads -- soft silicon for a safe grip. And a temperature probe is included for heating/cooling (HVAC) technicians.