The brutal competitive global market has forced manufacturers to produce the lowest standard permitted in a given 'local' market.
It was reported that cycle helmets sold in the UK today generally offer a lower level of protection than those sold in the early 1990s. This is due to the introduction of the European EN1078 standard. Be aware that a good helmet should meet the minimum EN1078 standards.
Good quality helmets are usually made of polystyrene, a material that is not known to deteriorate with age. Most manufacturers feel that it would be wise to change your helmet after five years of regular usage. So be warned, it is not a wise move to purchase a used helmet if you do not know how long it has been used.
Make sure you know how to wear the helmet properly as the effectivenss of protective headgear in an accident is influenced to a very large degree by the fit on the head and the correct wearing position.
Here is an advice from Snell Memorial Foundation:
1. Position the helmet on your head so that it sits low on your forehead.
2. If you can't see the edge of the brim at the extreme upper range of your vision, the helmet is probably out of place.
3. Adjust the chinstraps so that, when buckled, they hold the helmet firmly in place.
4. This positioning and adjusting should be repeated to obtain the very best result possible.
5. The procedure initially may be time consuming. Take the time.
Some of the known helmets that meet EN1078 standards or manufactured to Snell standards are: Aurora, AirForce, KidColbra, Deuce, Telluride etc. Take note that all the helmets from Specialized are known to meet the Snell and EN1078 standards.
Ref and more info:
http://www.cyclehelmets.org/papers/c2023.pdf-----------------------------------------------------
You won't go wrong if you get a Specialised helmet
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