ComStar's A/C Zero-Leak is specially formulated to stop small leaks in evaporators and condensers as well as around gaskets and seals. Permanent "Stop Leak" for A/C Systems & co-friendly. This environmentally safe product can be used in automotive, commercial, and residential A/C applications. Can be used for preventive maintenance and left in an operating system. Designed not to harm A/C systems, a non-hardening and polymer-freeCompatible with POE-based, PAG-based, and mineral-oil-based mobile AC lubricants A/C Zero-Leak contains no polymer, which means no clogs and no worries! This distinct advantage, unlike competing products, ensures A/C Zero-Leak will not form hard particles when it comes in contact with moisture in a system. Commercial and residential A/C applications, one 4 oz bottle is fit for up to a 12-ton system. A/C Zero-Leak can be left in an operating system. For larger systems over 12 tons use an appropriate ratio of approximately 1 oz per every 6 tons over the original 12 tons. As an alternative way to estimate the dosage necessary, please refer to the product attachments that show dosage by the amount of refrigerant charge that a system holds.