Any camping goods store will carry it. To make do, a black trash bag wrapped around your shower bag works well.
Pamela

Thanks Pamela
But I really dont understand how it works. But I will check out the camping stores .

Yolanda,
The one's I've seen are simply heavy black plastic bags with a hose and small plastic shower head. The black plastic heats the water in the sun and retains the heat longer than a clear or white one. Then you hang the bag above your head and open a nozzle similar to the ones on hand held shower heads. The water doesn't stay warm forever but can usually retain enough heat for a shower a few hours after sun down. We used them on the boat a lot. As I said, a heavy black trash bag works pretty well too.
Pamela.