Nu-Calgon 4057-55 A/C Renew 4oz Unpressurized Can Install with the A/C Re~New Injector (NOT INCLUDED) Nu-Calgon 4057-55 A/C Renew 4oz Unpressurized Can Install with the A/C Re~New Injector (NOT INCLUDED) A/C Re-New, formerly Zerol Ice, has been used successfully for many years to improve the performance of air conditioning and refrigeration systems. A/C Re-New provides significant saving in energy use. It also quiets noisy systems and extends the life of the system. It is a lubricant that blends with the systems oil, lasting for the life of the equipment.