The EasySeal Direct Inject by Nu-Calgon is the strongest HVAC sealant on the market today. Proudly made in the U.S.A., EasySeal already boasts over a million leaks sealed and now with this new injection system application is easier than ever. Just attach it to the valve on the AC unit and pump it through the system using liquid refrigerant. As it travels, the EasySeal formula finds leaks and creates permanent seals, getting the system running just like new. For any Micro Channel Coils, Packaged Systems, and Residential Split Systems EasySeal Direct Inject will get them running like new!