Emergency bivvy sack

I plan to add emergency bivvy sacks to my car's kit.

Does any of you guys (and/or girls !) know the difference betweem those two products, found on Aeromedix web site :
- Thermo-Lite Emergency Bivvy Sack
- AMK Headsheets EmergencyBivvy Sack

Is there any difference in thermal isolation, re-usability, strength, aso... ???
<img src="/images/graemlins/confused.gif" alt="" />

I have already replaced my old survival space blankets, with new AMK orange survival emergency blankets, which seems much more stronger and larger.

TIA

Below is a link to a review of the AMK Bivvy done by ETS member romania. I purchased a couple of them based on this review.

AMK Heatsheet Emergency Bivvy Review by romania

And here is a link to his review of the Thermo-Lite bivvy.

Thermo-Lite Bivvy Review by romania

Hope this helps....
smitty

Romania did a review of both of these.
Heatsheets bivvy
Therma lite bivvy

thanks, guys ! Exactly what I was looking for.

I was a bit busy, last semester and missed quite a lot of posts, including these two.
And when I performed a search on the forums this morning, I used the word "bivvy", not "bivy" ... <img src="/images/graemlins/confused.gif" alt="" />

So, after reading Romania comments, I guess I will go for the new AMK Headsheets bivvy.
Thx again.