Capacity: 2L , 4L , 6L and 10L
Hydrating on trips has got to be one of the most dynamic issues affecting adventurers. For the last few years we have seen an evolution in design from metal canteens to PTFE bottles, to bladders and just about everything in between and to be honest they all seem to have their benefits and detractions. For me the idea set up would be a bladder that was burly enough to take abuse compactible to go unnoticed in a pack when not in use and easy to fill with a filter. And while Sea to Summit's Pack Tap manages to nail a few of them it still misses the mark for the awesome-est of the awesome.
The idea that Sea to Summit is expanding on is finding a way to meet the majority of the minor issues that folks have with methods of carrying water and find the next best fit. Living up to it's namesake Sea to Summit was thinking of it all. The Pack Tap has 3 lashing points that allow you to fasten the bag to a kayak, or a backpack, or a tree with ease. The Pack Tap comes in 2, 4, 6, and 10 liter versions and each one is what appears to be a Mylar sack with in a pretty bomber ripstop bag. Holding a capacity of 203 fl oz for the 4.4 oz (for the 6L bag) dry weight this system is amazing considering the weight to carry capacity is 46 fl oz per 1oz of material weight.
The fill system is pretty basic, simply remove the valve by prying it off of the neck of the bag and fill. Although it should be noted that the opening is only about 1" in diameter which means filling it from a filter can be troublesome. Once filled recap the bag and you are good to go. However I have a bit of concern about possible pulling the rubber spout from the bladder if I use any appreciable force or twisting that is likely because as we all know the tougher it is to remove a lid the more we want to twist and turn rather than pull straight out. There is no need to remove the bladder from the bag other than should you need to replace it.
I found that lashing the bag to a horizontal surface like the hull of a boat served only as a means to transport the water, you cannot drink or pour out of it. I think that for Kayak or other horizontal mountings in which you would want to drink from it on the move that it would be neat for Sea to Summit to figure out a way to fit a straw or drink tube to the bladder to ease in use. However we should keep in mind that this is a way to carry water not necessarily a way to drink on the move.
All in all this is a neat and light weight way to bring additional water with you in a system that can just as easily be stashed when not in use as hung when you need it. I really dig it and look forward to many many well hydrated trips in the future.