Sawyer knows water filters, having been in the business since 1984. All that great rock and roll must have done something good, because they continue to lead innovation in the important area of helping us not puke our guts out because we drank some skank.
The Micro Squeeze is Sawyer's smallest and lightest filter, at roughly 4.5 inches long by 1.5 inches in diameter and a weight of just over 2 ounces. It's a simple design, basically a standard screw-on pop-top drinking nipple on top of a very small, 0.1 micron hollow fiber filter. The tiny pore size means it can filter out bacteria, protozoa and cysts, but not viruses: for that you'll want chemical tablets - we like Potable Aqua - which you should be carrying anyway as a backup in case your filter goes down.
The Micro Squeeze is as easy to use as it is to carry: just attach it to the included 32oz bag that you've filled with water and squeeze firmly but gently. Out of the box it takes a bit of effort, but it gets faster once you've used it a bit. The Micro Squeeze is also versatile: you can attach the included straw to the the filter and drink directly from a water source, all survivalist-like, or you can attach it to your hydration bladder hose.
The Micro Squeeze comes with the bag and cap, straw, cleaning syringe and coupler and an extra gasket. For the price it's a great deal and with proper care and maintenance should last a long time. As with all filters, read the instructions to find out things like, for example, you're not supposed to freeze it. Overall we really like the Sawyer Micro Squeeze, because it's effective, versatile and won't weigh you down.