Star brite® Winter Tech -50°F (-46°C) Marine & RV Water System Antifreeze provides cold weather protection for drinking water tanks and systems and holding tanks at an attractive price. The alcohol and propylene glycol formula will not arm aluminum, copper, brass or solder, with a bright pink color for excellent blow-through visibility. This product is ready-to-use; do not dilute it. Star brite® Winter Tech -50°F (-46°C) Marine & RV Water System Antifreeze will provide burst protection to -50ºF (-46ºC) and freeze protection within a range of +17ºF (-8ºC) tp +21ºF (-6ºC). Because it contains alcohol and propylene glycol, neither a PG nor an alcohol refractometer will provide an accurate freeze point reading. Note: This product is not recommended for use in engines; the alcohol blend may evaporate more quickly than Star brite® Wintersafe -50ºF and thus could lead to less protection in late winter. To protect engines, we recommend Star brite® Non-toxic Antifreeze. Note: The burst point of PVC pipes used in most drinking water systems is about -10ºF (-23ºC). When winterizing water systems in regions where temperatures can fall below -10ºF (-23ºC), we recommend using either Star brite® -100ºF or -200ºF (-73ºC) Antifreeze, choosing the appropriate formula for local conditions.