Here is a couple of videos of the 'Soldier Filter' in use.
https://www.youtube.com/watch?v=5mdSEV0O_4s&feature=youtu.be
https://www.youtube.com/watch?v=-1fXS9iyGqk
https://www.youtube.com/watch?v=TYg9tRm0Wvw
I was so impressed with the video reviews I have seen for the "Soldier Filter" (sometimes called the "Paratrooper filter" in the US), that I decided to return my unused MSR Trailshot and get my money back. I have now ordered a Soldier filter, for under £18 with free postage, direct from China. There are two versions available...One comes with a draw cord carry pouch printed with a digital woodland Camo pattern and the other comes with a hard carry case, very much like the one you carry a pair of glasses in, but slightly bigger...I went for the drawcord pouch as it should be slightly lighter. A couple of things I picked from the review videos: 1) The O-ring on the filter's plunger is lubricated in the factory with some form of grease. This grease has a "chemically" taste to it which is passed to the first couple of litres or so of water that is pumped with it, so you need to either discard the first 2-3 litres of water you filter with it, or before use, take out the plunger and wipe the grease off it...Water itself is a lubricant so it's probably not essential to lubricate the O-ring, but if it is, then I would use a very light coating of cooking oil rather than grease, as it is edible and doesn't have much taste to so it won't taint the taste of the water so much. One reviewer mentioned using "plumbers grease" to lubricate the O-ring...I am assuming this is some sort of non-toxic grease that has very little taste to it, but to be honest I really don't know.
2) Under pressure the angled outlet pipe fitting on the top of the filter body can pop off. The easy solution is to keep it pressed down with the thumb of the hand you are holding the filter body with, while you pump with the other hand.
3) Replacement ceramic filters are available for under £13.
4) One reviewer complained that he thought the outlet tube was too short...Both the inlet and outlet tubing can be swapped for longer tubing if you wish.