Vacuum contactors are used to switch capacitors, transformers and electric motors where overload protection is separately provided. These contactors are well suited to heavy-duty applications in harsh environments. The power contacts are sealed in ceramic tubes, called vacuum interrupters or vacuum bottles, where the air has been evacuated. Contact modules are UL component recognized and CSA certified. This contact kit is use with NEMA Size 4, 5 or 6 vacuum contactors. This contact is UL Listed and CSA certified.