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 harm 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 -50 ºF (-46 ºC). Because it contains a blend of alcohol and propylene glycol, neither a PG nor an alcohol refractometer will provide an accurate freeze point reading. However, a PG refractometer is still a great reference tool to ensure the product is within specifications. If your PG refractometer shows a reading between +21 ºF to +25 ºF (-6 ºC to -4 ºC) or stronger, that indicates the formula is within spec and ready to use even though the actual freeze point of this blend is much lower.Note: This product is not recommended for use in engines; the alcohol blend may evaporate more quickly than Star brite ® Wintersafe -50 ºF 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 -10 ºF (-23 ºC). When winterizing water systems in regions where temperatures can fall below -10 ºF (-23 ºC), we recommend using either Star brite ® -100 ºF or -200 ºF (-73 ºC) Antifreeze, choosing the appropriate formula for local conditions.FeaturesSafe for copper, brass and all types of plasticProvides burst protection to -50 °FPropylene glycol and alcohol formula is safe for all water and holding tank materials