These Forty Below® Camp Booties are insulated with a continuous filament polyester fiber, so they dry fast if they get wet. They also provide insulation even if wet, as compared to down/feather insulation which provides no insulation when wet, plus may not ever get dry again during a trip.
This synthetic insulation goes completely around and under your foot. The insulation is a continuous filament polyester fiber, that has been laminated to one side of the shell fabric for stability and also silicone treated to resist bunching of the fibers and allow for better moisture evaporation. This unique synthetic fill has shown to not typically bunch/clump-up or compress over time as with most other insulation types.
They are very compact, and superlight at only 345g per pair size large! The sole is made of a special waterproof rubber material, about 1-2mm thick, that is essentially a rubber/polymer blend that is embossed into a fabric. This gives it the properties being flexible at super cold temperatures, and grippy with small dot shapes across the entire bottom. There is also a 7.5mm thick closed cell foam insole. There is a Cordura nylon rand around the lower bottom, taffeta nylon upper, and taffeta nylon lining to make them easy to take on and off with wool socks on. Drawstring with cordlock top closure. The tape laces offer a great way to add support not found in most camp booties. The laces are made of a 5/8" wide thin nylon webbing that simply crosses over the top of the foot, and goes around the ankle and ties in the front. This adds virtually no weight and no bulk as there are no buckles or hardware to get in the way, or cause discomfort when using them inside a mountaineering boot shell around camp. You can also take the laces off and replace with any other lacing, cord, or homemade buckle/strap/Velcro.
345g/pair of Large approx.