This is a Costa Rican hot shower head. The way this works is there is a heating element inside the plastic container. The water flows over the element and comes out hot on the other side. You control how hot by how strong you turn on the water -- high water flow gives you lukewarm water, low water flow gives you a nice warm shower.

But for God's sake, don't touch the thing!

I have only cold showers in my house in Limon, so I was counting the days until I could have a warm shower in Dona Ivania's!