The Robinair LD3 by OTC is an Economy Refrigerant Leak Detector is an entry-level leak detector that is compatible with most commonly used refrigerants today including R-1234yf and R-134a. The LD3 uses an audible alarm to alert technicians of leaks and is equipped with a stable sensor that will last up to 10 years. The LD3 meets all current industry leak detector standards and is covered by a 2-year warranty. Uses 4 AA batteries, included.