A fairly simple design comes together to form the Airpod, a battery backup air pump. Air pumps are useful to oxygenate the water in case a power failure were to happen. Without oxygen, your fish are as good as dead. This Airpod gives power for up to 150 hours which is actually quite good considering the retail price is about $52. You will have two outlets to work with via a control knob, how it balances the power between the two is beyond us and up to you to figure out. It works off of 4 D batteries which your responsible for buying naturally, so don’t say we didn’t warn you.