I used a Volt jacket on my 1047 mile walk around wales last summer, its was great until the little bit of plastic on the zipper broke that goes into the part of the zip that you pull up with. Got a replacement straight away though
Exactly the same happened to mine. I replaced it with a Montane Minimus mountain jacket. simply because it that bit is metal.
Sadly the montane has delaminated, somthing that did not happen with the volt- Looks like the stretch of the volt helps with that.
That's the one I am using in the photo above. As I say, on their own they will not compress the mat effectively or even at all but, if you do as I do and use them to store your complete sleep system (mat and bag) then they compress the contents very well.
Looks like this when packed, That is, Downmat 7 (folded in half lenghways and rolled) + minimus (rolled aound the downmat). drybag is a medium size. They should fit into the small version too which will probably give better compression.