I've been using this helmet for three months, and this is what I think after covering 2500 miles in that time.
What’s good? The £599.99 C4 is the first flip-up helmet I’ve tried and I like the versatility. It’s comfy, light and very quiet. Aerodynamically it works well and it’s stable, with no buffeting. The venting is excellent – feeding a steady flow of air through the helmet. There’s a wide field of vision, thanks to the design of the visor and anti-fog insert and the integrated sun visor is great too. It is also easy to use, with an excellent lens. Built-in speakers and a microphone make for simple connection to a sat nav, which works well. I’ll be trying out the intercom on a trip to France later this year.
What’s not? The release mechanism to lift the chin bar took some getting used to and still catches me out.