The 4 and 5 pins are all single-pack relays, that is, there is only one coil and can only control one channel.

①Normally open contact: Pins 85 and 86 are internally connected to the coil, and externally connected to the control terminal, such as switches, output control signals,

Electromagnetic relay: an electrical relay that works by using the suction effect of the current in the input circuit between the electromagnet core and the armature.

Rated voltage, this is the voltage required for the relay to work normally. Different models have different voltages. Some are DC and some are AC.