One 1 Channel 5V / 12V Relay Module Board Shield with Optocoupler Support High and Low Level Trigger for Arduino|relay module|1 channel 5v relaychannel 5v relay module - AliExpress
How to Use a 12v Battery to Power an Arduino Uno and 2-12v Lights - #15 by groundFungus - Project Guidance - Arduino Forum
One 1 Channel 12V Relay Module Board Shield with Optocoupler Support High and Low Level Trigger Power Supply Module for Arduino: Amazon.com: Industrial & Scientific