Bike helmets are as much of a pain when they are not on your head as when they are- what do you do with it? Most people use U-locks, and if the helmet designers gave a moment's thought to the issue, they could adjust the hole pattern so that you could actually put a U-lock through them. But they don't, so you either have to carry your helmet around with you or leave it on your bike and depend on the kindness of strangers.
This wasn't good enough for inventor Blake Mills, so he developed this nifty little Helmet Lock.
You just feed it through one of the slots on your helmet and voila, you have a big vinyl covered wire loop that easily connects to the U-lock. Blair says:
I actually found myself riding more often and enjoying myself more after solving this simple little problem. And now I want to solve it for you too!
I have a real soft spot for the inventor in the garage, working away to solve a problem. So before you complain "it's just a piece of wire rope, a nut and a ferrule!" remember that he thought of it and you didn't. $ 12.95 (less in quantity) at Helmet Lock