Forty Below Purple Haze™ Overboots

54321    2 Customer Reviews


A favorite insulated boot cover choice for use on Denali, Himalayas, and Polar expeditions.  Patterned to fit double plastic mountaineering boots.  It is a very unique overboot in that it can stretch to fit easily over a wide range of double shelled mountain boot models, and the large volume “combi-boots” such as those from Millet, La Sportiva, etc.

The Forty Below® Purple Haze™ model uses a special nylon covered, 4.7 mm stretchy neoprene closed cell foam insulation, with 2 layers of heat reflecting Titanium, which goes completely around and under the boot, with no gaps in the insulation.  The insulation panels are glued together, and also stitched on the inside and outside surface, with no sewn through seams.  They fit trim to the boot, and are not bulky.  They fit with a wide range of crampon binding styles such as “step-in”, “new-matic”, and  “strap-on” crampon bindings, as well as wire toe ski mountaineering bindings.

The toe and heel area have small triangular shape panels made of a slightly thinner neoprene insulation that allows for many wire toe bails and flip lever heels to simply compress the insulation and rest on the toe and heel groove of the boot.  The toe, heel, and lower side area of the overboots have a thin rubber paint applied to add abrasion resistance and help protect the stitching.  The closure is in the front using a large size YKK® HEAVY DUTY zipper, with a flap underneath to help keep snow out.

Specs Sizing Reviews
  • Weight:  1lb 8 oz. (672g) per pair size Medium.
  • Fits over double shelled mountaineering boots.
  • Completely stretchy to fit a wide range of boot models.
  • Fit with a wide range of crampons styles.
  • Stretchy and easy to put on in the cold.
  • Easy to repair

This chart shows the overboot size as it compares to the sole length of the boot it will actually cover:

Size Boot Sole Length
XS 10-11"
Small 10.75-12"
Medium 11.5-12.75"
Large 12.25-13.5"
XL 13-15"


Reviews for the Forty Below Purple Haze™ Overboots


5/5 stars based on 2 reviews.

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These worked great as overboots and as camp boots over my booties. Also as insulation when your feet are in the snow cooking, putting on boots or whatever. On summit day they kept my toes from ever getting seriously frozen; very comfortable even at -10 with heavy winds.

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These are the standard on Denali, especially since Mountain Hardware and OR stopped selling their models. I've used the Outdoor Resarch (OR) model, which is not neoprene. The Forty Below neoprene overboots are best for wearing with boots and crampons, since they are very sleek. However, the neoprene absorbs some snow and water, so for wearing around camp, the OR model is nicer since it has more traditional fabric that keeps your feet drier. This version has neoprene all the way up the leg. The K2 Superlight version has neoprene only until the ankle and then switches over to a thinner fabric that serves as a gaiter.

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  • Purple Haze™ Overboots


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