Profile Century makes a good Clipon Aerobar. It's what I use.
A couple of points to be aware of with aerobars.
- They make the bike VERY twitchy when you are down on the aerobars, there is a huge difference in handling.
- You cannot reach the brakes quickly, so have a larger zone of awareness
You do get a significant reduction in air resistance and perceived effort in a headwind though
They are NOT good for situations that require critical bike handling though, such as group rides or rough surface conditions.