When pros train in Belgium they put on fenders like the SKS Raceblade. Why? Because rain or shine they're riding -- and don't want soaked backsides and legs. The Raceblade keeps you dry from road spray, and goes a long way to prevent the bike from getting waterlogged and otherwise trashed.
The Raceblade uses a rubber grommet system for attachment and literally takes 10 seconds of tool-free time to put them on and take them off. They stay firmly in place, but they won't mar your frame -- be it a steel or alloy frame with glossy paint, or a carbon frame with a lush clear coat. Take these on and off for season after season and your bike won't look any different for it. In addition, they're light and nicely aerodynamic.
The Raceblade fits 700c wheels equipped with tires ranging in size from 18-23mm. They're available in two colors: Black, and Carbon.