Platypus GravityWorks 4L Water Filter

Pros Fast Effortless Clear “clean” water bag Secure quick “ziploc” closure Light weigth (12 oz) 8L of water at camp Available charcoal filter add-on

Cons No pre-filter Non-adjustable hanging strap Clear plastic “dirty” bag (durability) Difficult to fill in still of slow water Bottle adapter not included

Used this filter for the first time in the High Uinta Wilderness area near Tworoose pass near 10500 ft elevation.

The filter is composed of two clear bags of some kind of soft tough plastic material. According to the Platypus web site, the bags are two layers of mated material. The bags are clearly marked for "dirty" and "clean" water. First impressions of the bags left me very concerned about their durability. I have not used them enough to form a good answer to the durability problem, but I worry because if the "dirty" water bag is punctured, then it is all over. The "clean" could spring a leak, and I could use the "dirty" as an on demand filter is camp. The dirty water bag uses a double "ziploc" method to close, interesting. The filter itself seems very fragile as well. Enough first impressions.

The opening to the "dirty" water bag actually worked very well. It is a smaller opening, but it does close very well. The hanging strap is not very will thought out. it is fixed length, goes through each corner of the back, thus causing the bag to be pulled hard against the tree that you hang the bag from, unless you can find a branch big enough to hold the weight, and long enough to hold the bag away from the trunk. The strap does have a quick release buckle, but the lack of length really hurts the design. The lack of a pre-filter to keep larger particulates from the filter is also a negative.

The water source I had was clear, but slower moving. I had great difficulty in filling the bag, which I did twice to get 8L of water. However, once the bag was full, and the filter and clean water connected, I had 4L of clean water in a few minutes, will doing nothing but admiring the scenery. I was very impressed.

After filtering 8L I did a back flush, and instructed by the manual, and server large particulates and some other debris came back into the dirty water bag. The back flush was simple, and effective.

Bottle attachment and charcoal filter are available as add-ons

Hose	Filter	Optional Charcoal
Dirty Water Bag	Bags	Bottle Attachment