Insotect Gear Lingo
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Insulated Gear Lingo

In the world of insulated gear there is a distinct language used by gearheads and casual outdoor gear enthusiasts. It is important to decipher some of the terminology and lingo to better understand your insulated gear and its performance.


Internal chambers within insulated gear that provide the housing for insulation material. Baffles can run horizontally and now - with the innovation of FlowGates - vertical baffles are becoming more prominent.


A measure of mass applied to fibers and yarns relevant to shell material of outdoor gear. Larger numbers indicate thicker, heavier, more-durable materials. Ultra-light yarns start at as low as 10 denier, 30 is standard and 50 is burly for use in a sleeping bag.

Draft Collar

A tube or collar that blocks drafts form entering a sleeping bag, boosting warmth for winter and three-season bags. This insulated tube is designed to prevent heat loss from around your neck and shoulders.

Foot Box

The flared, boxed, or barrel-shaped bottom of a sleeping bag designed to accommodate the protrusions of feet better. In some mountaineering bags, additional room is added to the foot box to accommodate boots or water bottles.

Zipper Flap

An insulated tube or flap that runs parallel to the zipper in order to block heat loss. The tube is attached to the lining material, since sewing through the bag creates holes that allow air leaks. Cold weather bags may have two thickly filled draft tubes.

Continuous Filament Insulation

A type of synthetic fill that consists of hundreds of thousands of parallel, interlocking strands of fibers that don't clump or fall apart.

Short-Staple Insulation

A type of synthetic fill made from short strands of densely packed fibers. Short strands maximize loft and compressibility.

Fill Power

A measure of the loft or "fluffiness" of a down-filled product that refers to the amount of space - in cubic inches - occupied by one ounce of fully lofted down. The higher the fill power the more trapped air an ounce of the down can trap, and thus the more insulating ability an ounce of the down will have.


Relative measure of the ability of insulation to provide warmth. One CLO is defined as the amount of clothing required by a resting (sedentary) person to be indefinitely comfortable at ambient conditions where temperature is 21C (70F), relative humidity is less than 50 percent, and wind velocity is about 0.9 kilometers per hour. The lowest CLO value of 0 (ZERO) is that of a nude person, the highest practical CLO value of 4 is that of Eskimo clothing (fur pants, coat, hood, gloves, etc.). Winter clothing has an average CLO value of 1, and summer clothing closer to 0.6


A measure of thermal resistance in reference to insulation efficiency often used to compare sleeping pads.


A property of down-filled gear typically measured in Fill Power which reflects number of cubic inches one ounce of down will fill under specific conditions.

Mummy Bag

A sleeping bag shape that tapers from the head end to the foot end, reducing its volume and surface area, and improving its overall heat retention properties. Some mummy bags are designed specially to accommodate women's body shapes. Most mummy bags do not unzip all the way to the feet.