OXford Huff breath deflector - £7 delivered
 

As above.

I bought this when I bought my Shoei Raid II helmet, but I couldn't really get it to fit comfortably (without constantly having to move it about) and so its not been used properly (its been put in the helmet, then detached and reattached a few times in an attempt to get it fitted properly. It hasn't been used out on the road or for more than a few minutes) It does need either some double sided tape to attach it to the helmet, or just some velcro strips to stick inside the helmet. It might be me being cack handed, but i'd say its probably not suitable for a Shoei Raid helmet.

It looks like this.

http://www.oxford-shop.co.uk/item3235.htm

£7 delivered, or £6 to one of the Soho lot if I see them there :)