The Techno Tools Dual Mode Refrigerant Leak Detector, No. D440A-UV, features two refrigerant leak detection modes, a solid electrolyte gas sensor and a patented UV dye detection system. The instrument is certified by a qualified independent laboratory to comply with SAE Standard J2791 and J2913. It has a unique digital leak size indicator that takes the guesswork out of whether or not to repair a small leak. The D440A-UV does not require rechargeable batteries.