Using the sniffer probe, the helium leak detector is able to detect specific amounts of helium leaking from a defect in a pressurized system. Generally, sniffer leak detection is used to locate leaks in parts or systems so that they can be identified and repaired. The part or system is first pressurized with the tracer gas. The operator then systematically scans suspect leak locations with the sniffer probe in order to identify a possible leak. The skill of the operator and the technique used can dramatically affect the results which is why the sniff probe method is not considered a quantitative leak testing method. Nevertheless, with the use of calibrated instruments, calibrated leak standards, and well trained operators, quantitative measurements can be made. The sniffer probe method can detect leaks over 100 times smaller than what can be detected using the old and outdated bubble method.