BJ Williams Big Blue Micro Leak Detectors are the trusted choice for OEMs and industry professionals worldwide. This original Big Blu leak detector is the only bubble/foam solution capable of detecting gas leaks as low as 0.65 ounces per year. Safe to use on all gases, including oxygen, it is biodegradable, NSF, and Kosher certified, making it safe for use around food and on all metal surfaces. Its ultra-sensitive formula ensures accurate leak detection for a variety of applications.