Unfortunately, the cheaper version of the Metro is one-size-fits-some, while the Metro comes in a couple of different sizes. If you have a big melon, you'll probably need to go for the more expensive one. Whatever helmet you go for, I would respectfully suggest that you shouldn't let price supercede comfort/fit in your selection criteria. If your helmet fits comfortably, you're more likely to want to wear it and it's more likely to stay on when you crash.