Review on LotFancy Freon Leak Detector: Ultimate HVAC Refrigerant Gas Leakage Tester for Home & Professional Use - CFCs, HCFCs, HFCs, R134a R1234yf R410a R22 R11 Compatible, High Accuracy & Indicator Light by Aaron Richardson

I'm writing this review after receiving a second unit that didn't work. When the first one arrived, I put in new batteries and turned it on. There was no indicator light as described in the instructions which should be green when the batteries are good. Ember if not. Thinking I might have misunderstood the lamp's purpose, I pulled the block out and placed it a few feet from the Freon tank, releasing a small amount of refrigerant. No signal. Thinking I might have received a defective unit, I processed the return and ordered a second one. Arrived today and doesn't work either. I was concerned about the price and the fact that the next other leak detector is $150 and this one is $21. I am returning both units and I am confident that I will look for a more respected brand at a much higher price.