I purchased this for general automotive a/c work (R134a).  Have successfully pinpointed leaks on several different vehicles.  One hose leak, one condenser leak, and one leak at a 0-ring fitting.  These were very slow leaks, and this unit made finding them easy.  I used it at the highest sensitivity setting where it was still quite stable.  Take your time and carefully explore around everything that has refrigerant in it, even areas where you don't expect a leak.  You will find the leak with this unit.  False positives are infrequent.  Also used it to find a slow leak in an R410 home system.  I am very satisfied, and recommend this unit.
I purchased this for general automotive a/c work (R134a). Have successfully pinpointed leaks on several different vehicles. One hose leak, one condenser leak, and one leak at a 0-ring fitting. These were very slow leaks, and this unit made finding them easy. I used it at the highest sensitivity setting where it was still quite stable. Take your time and carefully explore around everything that has refrigerant in it, even areas where you don't expect a leak. You will find the leak with this unit. False positives are infrequent. Also used it to find a slow leak in an R410 home system. I am very satisfied, and recommend this unit.