It doesn't need batteries, it gets power from water flow, so it have a small turbine inside to generate power. If the water flow is big, it makes noise. It doesn't change color, only blue It don't help children to avoid scalding water It's not so small A bit noisy I thought It changes color the I... It doesn't need batteries, it gets power from water flow, so it have a small turbine inside to generate power. If the water flow is big, it makes noise. It doesn't change color, only blue It don't help children to avoid scalding water It's not so small A bit noisy I thought It changes color because the description says that helps chlidren to avoid scalding water, but it seems to be another model that shares the same box. I will search for another item that changes color. Better if it's smaller than this. Read more