Gear Watch: Marmot Plasma Sleeping Bags

Marmot has set a new standard for ultralight puff. Their new Plasma sleeping bags are stuffed with certified 900-fill goose down, the highest fill power rating for any sleeping bag on the market.

The Marmot Plasma 15-degree bag weighs in at a mere 30 ounces for the regular length ($469), 31 ounces for long ($489). The 30-degree version is 22 ounces ($419) and 23 ounces ($439), respectively. The Plasma series also incorporates some unusual design features, including vertical baffles that run the length of the bag and are designed to keep down from shifting to the sides and creating cold spots.

The Plasma bags feature a slightly narrower shoulder and hip girth (60 and 58 inches, respectively) than other Marmot bags (typically 62-64 inches), which keeps weight down but may fit more snugly than other Marmot bags you have used.

Fill power is a measure of how much volume an ounce of goose down takes up (measured in cubic centimeters) under standard laboratory conditions. Higher fill power down is thus warmer for its weight than lower fill power. For example, a sleeping bag filled with 900-fill down will be 50 percent puffier—and thus much warmer—than a 600-fill bag stuffed with the equivalent weight of down.

Most commercially available goose down hovers in the 550 - 650 fill power range and is harvested from commercially raised young geese slaughtered for food. Higher fill power down comes from older geese and must be meticulously sorted (often by hand) to select only the largest, puffiest down clusters. Most high-end down is in the 750 - 850 range.

To obtain 900-fill down, the selection standards must be even higher. Only the largest down clusters are selected, all of which come from older geese. The price reflects the rarity and difficulty of obtaining such high-quality down.

Like most Marmot down bags (check out my 2009 post on Marmot sleeping bags), the Plasma series is as drool-worthy as it is expensive. They are available exclusively at REI until mid-January (the bags aren't even on the Marmot web site yet).

Here are the relevant REI links, which include links to an amusing 3-minute YouTube video about the bag:
15-degree Plasma
30-degree Plasma

Equipped” is an AMC Outdoors blog, written by Matt Heid.