One of the most important tasks of today’s technician is refrigerant management, and specifically leak detection. For this job, the technician requires a quality, effective leak detector, and Cal-Blue Plus meets that need. Cal-Blue Plus has outstanding freeze-protection down to 5ºF (and up to 225ºF). Nu-Calgon 4182-24 Cal-Blue Plus Leak Detector (1qt. Spray Bottle)