This patented 'Water Bloc' (WB) construction by Exped is another notable evolutionary step in the sleeping gear field. Imagine combining a waterproof bivvy system into a high-end sleeping bag, reducing the need for, and excess weight of, another shell fabric layer in between, and thereby increasing breathability.
This system has worked so well for Exped that other large outdoor gear players wanted in on the action and purchased the patent, some doing well and some bombing missing the point altogether.
Exped continue their WB constructed bags in a renamed 'Waterbloc' line with models differentiated by their down fill eg. 'Waterbloc 600' is the new name for 'Ibis'.
Our staff and customers have used these extensively far and wide. There has been only praise to date (since their arrival at Mountain Equipment in February 2007). One user even claiming to have used them in rain, sleet and snow during open Patagonian bivvies with no complaints - just put your rainshell over your face.
We would suggest for those experienced enough, a Waterbloc 600 would suffice for mostly fine open bivvies during a New Zealand summer whilst tramping or mountaineering. A "too hot for huts" bag that time of year but usable as such due to its full length side zipper. Used in conjunction with an Exped Downmat and a tarp or tent fly you could find yourself braving wintry Tasmanian traverses and who knows what else.
If you were to factor in a 500g fill goose down bag at 1100g total, bivvy sack - at the lightest 600g and a 3.8cm full length "Self Inflating" mat at 680g minimum with an R-Value of 3.8 at best, you would be looking at a total sleep system weight of 2380g.
Waterbloc 600: 1250g + Downmat Pump 7 (goose down and air filled sleeping mat): 880g (with an R-Value of 5.9) = 2130g... which would make for a considerably warmer and set-up.
Exped have a review link below:
