Personally i would never buy kit off ebay, especially helmet as you have no idea of the history of the products. Regarding helmets - all helmets sold in this country have to pass certain safety tests, so in some respect they all can provide a certain level of protection. However, they do not show which helmets far exceed the testing requirements and which just scraped by. I wouldnt spend less than £200 ish for a helmet to get a good quality one, that fits well and i like. I also prefer the well known names, as their are well known and well trusted for a reason. After all, would Motogp stars wear Arai/Shoei/Nolan etc if they werent going to do their job and protect them in the event of a crash?