A digital vacuum gauge called the VG-760 is used to measure vacuum precisely when filling refrigerants. It has an expert vacuum sensor for accurate vacuum testing. The purpose of an HVAC and refrigeration system's evacuation is to remove any moisture and air from the system, as these elements can react chemically with refrigerants and cause long-term harm to the system. In general, for the system to efficiently remove moisture, the system vacuum should be lower than 700 microns. A 300 micron vacuum is the best. This need cannot be met by common refrigerants. The VG-760 is a tool for determining vacuum pump quality and testing system leaks.