‘Flow Gate’ is Marmot’s name for the system that is the unique selling point of its new sleeping bag. Its purpose is to prevent mass migration of down through the bag, thus avoiding cold spots and keeping the user evenly warm all over.
The construction allows you to manipulate the down along channels within the bag, yet discourages further accidental movement of down while the bag is in use. So far so good; but I found it incredibly difficult to find out how the system works, and ended up having to ring Marmot to ask them. There are no instructions or markings on the bag to explain how to use it, which is a clear oversight. This is a shame, as the Marmot Plasma 15 happens to be rather good, with an impressive performance to weight ratio.
The Flow Gates are positioned about halfway down the bag, with another set a foot or so lower. I finally managed to find them by running two fingers down the inside of the bag between the stitch lines. They feel a bit like a piece of material with a round hole in the middle. Once located, the idea is to massage the down through the holes, along the length of the baffle, moving the down through the Flow Gates as required. This means you can add extra insulation where you need it.
Despite the sleeping bag generally being very good at its job, I found the function quite a hassle. It’s not something I’d fancy attempting at night when camping and waking up due to the cold. But it could be useful if you just wanted to tweak the down distribution once, for example if you tend to get chilly feet. So, while Flow Gate clearly has some useful applications, it doesn’t offer the ideal solution to the problem of cold spots.
The Marmot Plasma 15 itself is super-light and beautifully comfortable. The price isn’t something to be taken lightly, but it’s hard to find a similar specification sleeping bag much cheaper.
Size 183x75x55cm regular (long version also available)
Outer fabric Pertex Quantum with DWR
Inner fabric Pertex Quantum with DWR
Construction vertical baffles
Insulation 500g of 900+ fill power goose down
Minimum comfort temperature rating -7.8 deg C
Packed size 19x32cm; 19x18cm compressed
Weight 856g (bag only); 880g (with stuffsack)
Made in China
Stockist details – tel. (015395) 63616; www.marmot.eu
The weight of the Marmot Plasma 15 is outstanding, making it an ideal sleeping bag for 3-season backpacking; but the Flow Gate function needs a clearer explanation for users.
Review by Graham Thompson
First published in Trail magazine Spring 2011