Rector Seek Better Bubble is a uniquely formulated leak locator that pinpoints the smallest leak quickly and easily. Its organic ingredients make it safer to use on most gases including ammonia, oxygen, air, and refrigerants. Its thick blue formula produces large, long lasting, well defined elastic bubbles that stand up under pressure and windy conditions. It may be used on surface temperatures from 0 deg. F. to 250 deg. F., is noncorrosive, will not attack rubber or plastic, and is biodegradable. 8 oz. bottle with dauber top.