Steve Rapp Technician at Kemberling Auto Sales & Service
We have 2 of these in our shop; one we bought new about 15 ago and is branded Yokogawa (before Bacharach bought the company), and the other is a Rotunda branded version of the same tool I bought used for myself off of eBay just to have a second one around during the busy season. They both work very well at finding even small leaks. You do need to replace the internal battery every 2 years or so, but if the battery is weak it will still work if the charger is plugged into the wall. It also takes a little practice to learn how to calibrate and adjust it accurately, so I would recommend playing around with it for a couple of weeks before A/C season starts just to learn it's limits.
Bacharach also makes an excellent refrigerant identifier that gives you % of air and flammables in the system before you start. Catching air in the system has been a great time saver before attempting a top-off or when diagnosing insufficient cooling concerns.