How effective are Shake Weights?

I was looking at adjustable dumbbells earlier after it was suggested that I try those instead of a kettlebell. While I was searching I found some shake weights that are supposed to tone arms, chest and shoulders, and they also let you vary the intensity of your upper body workouts.



Has anyone tried these and how good are they?

via Smart Health Shop Forum http://feedproxy.google.com/~r/SmartHealthShopForum/~3/hkVBrFyslE4/8432-how-effective-shake-weights.html