I picked this up for my friend who works part time with air conditioning. He used it to diagnose an air conditioning leak in his dad's car and then lent it to another friend of ours who used it on his fridge. The device is quite easy to use as it only has a few buttons. The instructions are simple but pretty straight forward. We are not air conditioning experts and have been able to diagnose and find leaks on various types of refrigerant based equipment.