What does the 550 do that a regular set of gauges and a thermometer will not?

1. Higher accuracy, the Testo 550 has 2-3 time the accuracy of analog gauges and does not easily go out of calibration
2. No need for a temperature pressure chart, the Testo 550 calculates saturation temperatures for every common refrigerant
3. Real-time superheat and sub-cooling. The 550 will calculate superheat and sub-cooling on systems when they are unstable like periods of low load. Because it tracks changes in real time it is easy to see min, max, and mean values on superheat and sub-cooling.
4. Temperature compensated standing pressure test. Using the temperature probe and the high pressure sensor, the Testo 550 can determine using Boyle's law if the system is leaking over time. Because pressure changes with temperature, this feature is useful when doing doing standing pressure tests form 10 minutes to over 24 hours.
5. Easier to read. Digital displays are easier to see for the user, and mistakes when interpreting saturation temperatures are harder to make.
6. Charge in the dark. So who the heck does that? We all have had to at one time or another. The Testo 550 incorporates a back light so you do not have to hold a thermometer in your teeth while charging.
7. Altitude compensation adjustment. No need for high altitude T/P charts. Also allow the user to gain additional accuracy when charging anywhere above sea-level.
8. Delta Temperature calculation. Great for checking temperature drops across filter dryers.
9. Gets the job done faster. Once the calculations are done for you it is hard to go back to hand calculations
10. Look more professional. There are better ways to do your job and the customer will notice too. Higher accuracy, better speed, and fewer calculation errors benefits everyone.  

Better jobs = better consumer satisfaction

Higher satisfaction = more recommendations

More recommendations = more jobs

More jobs = more profit

More profit =

Better toys

More vacations

Happy spouse

The list goes on and on……..