Description :

Timing from Microseconds to HOURS
Simple Circuitry
Precision Pulse Generation / Timing,
FMAX = 500 KHz
Use a single 4 to 16 VDC supply
Excellent temperature stability 0.005% / °C
Adjustable Duty Cycle
Countless Application and Information Sources

Chip (NE555) Characteristic :
When unconnected with the supply power, the state of the module is "NO" [ normal open ], CB and COM are conductive. CK and COM are unconductive.

When connected with the supply power, delay for 0-10s, the module will in the state of "NC" [ normal closed ], CB and COM are unconductive, CK and COM is conductive

Specification :

Module Properties : NE555 chip
Dimension : 77 (L) x 23 (W) x 18 (H) mm (with potentiometer)
Input voltage : DC12V
Adjustable time : 0 to 10sec
Control voltage : AC 0~250V / max. 10A, DC 0~30V / max. 10A
Max. loading : 2200W

Connection Drawing:

We suggest you using a diode connectiong to the VCC in series. In order to prevent from damaging chip of Power Reverse or Voltage Fluctuation. ( The board does not add diode because the power would not enough to pull-in the relay for the buck from diode when power is too low. )

Details pictures :