Yes it is - thanks for jogging my memory Eis -ex!!
I found this below - For anyone else who stumbles across this thread it clips on the regulator I think like this picture here:
http://www.starcruise.privat.t-online.d ... aturen.JPG
Truma ice Ex 12 Volt
The Truma EisEx prevented at temperatures below about 4 ° C to freeze the regulator by water residues or other residues such as oils.. In sub-zero temperatures remain liquid oils and the regulator remains functional.
Brittle or porous gas hoses should be necessarily replaced. During the winter should generally cold-resistant hoses, which are marked with a corresponding imprint may be used.
Thanks bud

1990 Atlantic Westy Pop-Top... 1.9TD