Meets all requirements of latest EN54 · Two-wire, polarity-free realizes convenient wiring · Completes EMC test, it has strong anti-electromagnetic interference ability, high stability and reliability · Dual photoelectric smoking sensing chamber provides intelligent and accurate detection of smoke · BLC algorithm automatically adjusts alarm threshold based on the smoke in the chamber, extending cleaning cycle and providing easier maintenance · Non-loosening screws on base terminal for easy installation · Contacts material is highly acid-resistant and rust-resistant