In reply to McGus: I cycle, mountain bike and compete in triathlon in my Rudy Project Rydon's. They are fantastic and way ahead of any of the various (and more expensive) Oakley's I have tried (bar the M Frame's which just look too '80's for me!)The arms bend to fit and grip your head, they are light as a feather and do not move an inch during vigorous excercise. I also got the clip on prescription lense attachment which is very secure and works faultlessly, easy to use and cost about £20. For the lenses the high street were quoting about £80 but I found a great place in Horsforth near leeds who really deserve a plug. They will do things by post and are great people and best of all charged me £25 quid for coated lenses!!! They are called D&J Optics (0113 250 8822, ask for Datzi). They are essentially a lense lab and only started selling direct to the public when they realised how much the high street were ripping people off!BTW No, I do not get a commission, just really impressed with them. Hope this helps.