The biorb intelligent led allows you to create a 24 hour lighting cycle as nature intended reducing the stress on your fishr r simply plug it in no set up requiredr sunrise daylight sunset and moonlight cycles change at the push of a button with 7 different cycles to choose fromr automatic 24 hour timer just plug the light in and it cycles at the same time everydayr no need to change a bulb lasts 50 000 hours using long life low energy cost saving ledsr safe low voltage 12 volt p