This is a brief heads-up to anyone looking to buy any of the 221/522/1090 SelectTech dumbbells by Bowflex.
Both 2008 and 2009 versions of each model are commonly being offered for sale on Ebay.
The 2009 versions are desirable as they enjoy minor design tweaks to address a couple of issues that became apparent on the 2008 versions.
Rather than paraphrase another website (Ebay's rules don't allow links) , here's the relevent part:
"In addition to an updated design Bowflex has greatly increased the strength and durability of the dumbbells and added new aluminum alloy and polymeric safety tabs"
This is because the 2008 model used a plastic component as part of the disc locking mechanism that was prone to breaking. Another benefit of the 2009 redesign is that it's easier to re-sit the dumbbell back into it's cradle after use.
How to identify the different versions:
The 2008 version has grey inserts across the weight discs.
The 2009 version has red inserts across the weight discs.