Viper RT150D Big Blu Subzero Freeze Resistant Micro Leak DetectorViper RT150D Big Blu SubZero is the most durable product of its kind for leak detecting under extreme cold conditions. The temperature rating is down to 30F. Bubbles will keep forming where other low temp products give out, freeze or become gelatinous. Features : Freeze Resistant NSF certified for use around food Non Corrosive Detects Micro Leaks down to 0. 79 oz year Safe of any type of gas Direction : Turn off or disconnect all power. Coat all