Useful Links

Bowflex 552 On Wikipedia
The dumbbell, a type of free weight, is a piece of equipment used in weight training. It can be used individually or in pairs (one for each hand).
http://en.wikipedia.org/wiki/Dumbbell

Bowflex 552 On Youtube
Best Adjustable Dumbbells - Bowflex SelectTech 552 Dumbbells
http://www.youtube.com/watch?feature=player_embedded&v=o-BFPcCAl98