Hi,
the german word is "BERGESACK".
If you google this word you will find a lot of different manufacturers.
All the german, austrian and swiss rescuers use different kinds. May be sometimes the same for a limited time, but there is allways a progress and changes.
If you need special advices give me a PM.
I will not recommend a single manufacturer but one of the most used is Tyromont. Take this as example
http://www.tyromont.com/bergesack.htm
Other manufacturers are Bornack or Faehrmann
http://www.faehrmann.com/sire1.html