NOTE: If you're set in your views about radiation and nothing's going to sway you, you may want to stop reading now, to keep your blood pressure low.
My personal opinion of this product (and of this company) is that they're preying on the fears and gullibility of new parents who - it's a great quality, don't get me wrong - want the best for their child. That being said, here are the reasons that I feel mothers everywhere are being duped by these products:
1) All three of the products that Belly Armor sells only protect against a very small section of the Electromagnetic spectrum (or radiation, if you want to throw the dreaded "R" word around). 10MHz to 8GHz. You can look on
this chart to see exactly how much of the spectrum this covers. This section of the spectrum does not include X-rays (doesn't work against the airport scanners), UV rays (sun), or Gamma rays (nuclear...sorry, this won't protect you or your baby against Fukushima). This product will not even protect you from the EM waves emitted by the motion detectors commonly found in every store you venture into. Yes, this will protect your uterus against most consumer electronic devices, HOWEVER...
2) In order to protect your baby, the waves coming off the device MUST be in line-of-sight with your belly band. So... yes, it will protect the fetus from the cell phone in your pocket or the WIFI you're using on your laptop, but it won't protect your uterus if you're standing under a cell phone tower.
3) Any risks associated with EMF emitting devices is still highly implausible and unproven.
4) Even for a product containing silver (their "active ingredient"), they're charging too much. I'll let you in on a little secret... any "odor repelling" article of clothing has just as much silver in it as the Belly Armor products. So you can spend $60 for a belly band (and don't get me wrong, you'll smell FABOO at the end of the day!), or you can buy an Under Armor T-shirt for $20 that will do the same thing...and then spend the remaining $40 on building up your surplus of diapers.
Sources:
http://www.theregister.co.uk/2010/09/15/tinfoil_bellywear/
http://www.sciencebasedmedicine.org/index.php/new-data-on-cell-phones-and-cancer/
http://en.wikipedia.org/wiki/Electromagnetic_radiation
http://en.wikipedia.org/wiki/Ionizing_radiation
http://en.wikipedia.org/wiki/Gamma_ray
http://www.bellyarmor.com/shop/belly-band
http://www.underarmour.com/shop/us/en/womens/apparel/tops
