This is the Canon EF 200mm f/2.8L II USM Telephoto lens:
Sample Photos
ModelMayhem.com – Portrait photo and discussion on how lightweight the lens is, and the great bokeh in photos taken using it.
Superb Major League Baseball Action Photos – Comes with a couple of tips on camera settings and lens accessories.
Resources
Official Canon 200mm f/2.8L II USM page at Canon USA.
Related
Canon lenses – Main page.