The SF6 relay gas density meter with pointer and scale installed on the SF6 circuit breaker is called the density meter; SF6 density relay or density pressure switch without pointer and scale. Some SF6 gas density meter also has electric contact, which doubles as density relay. They are dedicated meters for measuring SF6 gas.

SF6 circuit breaker, as a new type of high-voltage electrical switching equipment developed in modern times, has been widely used in power systems due to its superior performance, safety and reliability, easy maintenance and long service life, etc. A density relay is a relay that monitors air leakage from a sealed container.