This Battery Operated LED Emergency Beacon is shock resistant, waterproof and durable.
The unit is magnetic, allowing it to be attached to metal surfaces, and can be recharged using a 12V car charger or a 230V wall charger:
https://renametest.ng15hosting.uk/products/visual-warning-signals/battery-beacons/
Available in:
Red, Amber, Green, Blue, Clear and Yellow