Six Moon Designs Polycro is ultralight plastic sheeting, usually weighing 1-2 ounces, that many backpackers use as a tent footprint instead of the heavier tent footprints sold by tent manufacturers or Tyvek, another footprint substitute.  Polycro is waterproof and reasonably puncture-proof, making it an ideal protective barrier for ultralight tent floors or cowboy camping. You can also cut and shape it with a pair of scissors to the size you need to save weight or make it easier to manage.  I typically use the same sheet for a year or more.

Polycro is also sometimes called polycryo: the two are just different spellings of the same material. It’s also the same stuff sold in shrink-wrapped window insulation kits for covering drafty windows in winter, sold by companies like Frost King, 3M, or Duck Brand. A single piece lasts a long time, so the advantage of buying it from Six Moon Designs in smaller quantities is that it’s less expensive and you don’t have the extra cluttering your home until you use it, which might take years.

Trim the polycro to match the size of your tent floor

Each package of Six Moon Designs Polycro includes two 90 x 48-inch (large size) or 90 x 40 inch (small size) sheets, which are sufficient to protect most one or two-person backpacking tents. When pitching your tent, you typically start by placing the polycro sheet on the ground, then setting your tent up over it. But polycro can be difficult to handle in the wind, in which case it’s easier to weigh it down with rocks or just slide it under your tent floor once it’s set up and before you get into it.

When using polycro, you want it to match the size of your tent floor rather than extend more than an inch or two beyond its perimeter. This is to prevent water from pooling on the plastic if it rains and soaking your tent floor.

When its time to leave, fold the Polycro up and stuff it in an outer pack pocket

When you break camp the next morning, simply fold the polycro footprint and stuff it in an outer pocket of your backpack. It will likely be slightly wet from condensation, but should dry quickly.

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