This is one of the best pieces of kit I have seen. Strong, lightweight, good quality, and well designed. The iphone fits perfectly into cushioned interior. Strong clips lock in iphone and seal it in. Phone can still be fully used with access to all buttons and headset socket can also be accessed via a sealed plug. Can make hands-free voice calls while still connected to the bike. Can also run a charge lead into case. Using the supplied mount it fits easily onto handlebars of bike without need for tools. Quick release button allows quick removal from mount. I have recently used this case over a two day 170 mile ride running sat nav on the iphone. Even cycled through 1 hours heavy rain and it remained perfectly waterproof.
NOTE: Some reviewers said it had poor fixings and kept falling off the bike - this is not the case if fitted correctly. The case slides easily, and loosely, onto the mount but you then have to apply considerable force to click the two pieces together solidly. Once properly connected, they do not come apart easily and will not fall off the bike.