Every so often, someone goes a little mad with the green gadgets and makes something that’s just plain silly. The solar cap fan with a clip is designed to keep you cool by clipping onto a baseball cap and blowing air into your face. However, you will look strange, and no doubt you’ll get some very confused glances and laughs.
It’s a small fan (7.3cm in diameter), and probably quite effective. However, I’m sure that there’s a high chance it’d get knocked off or blown off; that’s assuming it doesn’t obscure your vision!
Source: UberGizmo