Techno Tools D440A solid electrolyte sensor refrigerant leak detector is certified by a qualified independent laboratory to comply with SAE Standards J2791 and J2913. It has a long life solid electrolyte sensor, and it is designed to detect all HCFC, HFC, HFO, and HC refrigerants.It has a unique digital leak size indicator that takes the guesswork out of whether or not to repair a small leak. The D440A does not require rechargeable batteries.