this is 1 channel relay module with the following spec:
Can be used as microcontroller development board module can be used as home appliance control5 V-12V to TTL control signalThe control signal DC or AC, 220V AC load can be controlled.There is a normally open and one normally closed contactA power indicator lightA control indicator, pull off, disconnect does not shineAransistor drive to increase the relay coil control pins high impedance.A control pin has a pull-down circuit to prevent malfunction relay vacant