Honest question here, and no, I'm not trying to start another 'wear a helmet versus don't wear a helmet' thread. I know that subject has been beaten to death a million times over (maybe this one has as well, and I just didn't word my search query well enough).

Rather, what I'm interested in knowing is what's the difference between a helmet costing $35 versus a helmet costing $200?

I'm looking at an e-mail I got from Performance Bike, and they're advertising a Giro helmet on sale for $139.99 (regular price $199.99).

For all intents and purposes, it looks just like my Louis Garneau helmet I bought off of eBay for $35.00.

Just wondering what the $200 helmet has that the $35 helmet doesn't.

Thanks for any and all comments.