Forty Below® K2 Superlight overboot
A favorite insulated boot cover, The Forty Below® K2 Superlight™ model has been used for many years on Denali, Himalayas, Polar expeditions, and cold wilderness uses around the world. Fits double shelled and single boots for mountaineering and expedition use.
UPDATE 7-12-21 Due to the continuing impacts due to the Covid Situation, we are have a limited supply in some sizes. Please see chart below for what we do have at this time, and information to get on the contact list when your size is back in stock.
Please see below for more details.
To Order: Please provide details about your boots and crampons in the boxes below. We will select the proper size of overboot for you based on your boot information. The crampon information is to be able to pass on any special fitting notes if needed.
Forty Below® K2 Superlight™ overboots
“I wouldn’t go to extreme altitude without them!” JIM WICKWIRE
Due to the Covid Situation impacts, we are out of some sizes. We are so sorry!!
We do have a few sizes in stock:
1. X-Small (fits boot sole lengths approximately 10.00″ to 11.00″ inches)
2. Small (fits boot sole lengths approximately 10.75″ to 11.75″ inches)
3. X-Large (fits boot sole lengths approximately 12.75″ to 13.75″ inches)
4. XX-Large (fits boot sole lengths approximately 13.75″ to 14.50″ inches)
5. XXX-Large (fits boot sole lengths approximately 14.00″ to 16.00″ inches)
Please call or email us if you think you might be in those approximate size range and we can confirm if you are, and set you up if so!
For all other sizes (Medium and Large), if you are interested, please email us with your boot details and date you need them by, and we can get you on our Reserve/Contact list. Thank you for your interest in our overboots!
Fits over double shelled mountaineering boots and over single mountaineering boots.
Stretchy and easy to put on in the cold.
Fit with a wide range of crampon styles.
Neoprene insulation around foot, breathable gaiter upper.
Easy to repair.
The Forty Below® K2 Superlight™ overboot is a great choice for extreme cold climbs. It is a favorite insulated boot cover that has been used for many years on Denali, Himalayas, Polar expeditions, and beyond.
Patterned to fit both double shelled and single style mountaineering boots. In addition to being used with double shelled boots for high altitude and cold weather climbs, they can also be fitted to leather climbing boots to help extend their temperature use range.
The Forty Below® K2 Superlight™ uses a special nylon covered, 4.7 mm stretchy closed cell neoprene foam insulation, with 2 layers of heat reflecting Titanium. This insulation goes from about the top of your climbing boot, 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. Because of the stretchy insulation material they are easy to put on in the cold, and they roll up small in your pack.
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. A 2 inch wide heavy duty velcro front closure goes all the way down to the toes for easy adjustment of laces. The upper gaiter goes up to just below the knee, and is made of a non-coated, windproof and breathable Cordura nylon to help minimize frost build up. Elastic drawcord top closure, with a cordlock on top of the gaiter. A special smooth nylon crampon patch is glued and stitched to the instep side of the neoprene for added resistance to crampon pokes, etc.
One of the great features of Forty Below® overboots is that they are easy to repair! This is especially helpful, as crampons and rugged terrain are so hard on everything they come in contact with. Repairing is easily done by simply gluing the poke holes together, using glues such as those for repairing neoprene fishing waders or wetsuits, like AquaSeal from McNett, etc. For the fabric gaiter repairs, the iron-on style fabric patches work well and are really easy to put on, and can in many cases eliminate the need to sew patches on. For repairs on the mountain, use the Forty Below® Repair Patches, which are a special sticky and stretchy tape that work great for repairs during a trip (one is included with the overboot).
These pictures below show the various types of crampon binding styles that can be used with the Forty Below® K2 Superlight™ overboots on the double boots and single boots:
Double Boots: For example: La Sportiva G2 SM, Scarpa Phantom 6000/8000, La Sportiva Spantic, Scarpa Inverno, Koflach Expe, and most others. Crampon bindings shown below are: “Strap-toe/flip lever heel”, “Strap-on”, and “Step-in wire toe/flip lever heel” (which may not show depending on the screen width of your phone/tablet)
Single Boots: For example: Scarpa Charmoz, Lowa Renegade, La Sportiva Nepal, and most other technical climbing models.
Please Note: Single boots will usually not fit with overboots and “wire toe bail” crampon bindings because of the lack of space on the boot toe groove for the combination of the bail and overboot fabric to properly fit, which is why they are not pictured below. Please contact us if you have any questions or would like to discuss this for your specific set-up.
WARNING: The user must try on the crampons to each boot and overboot combination to confirm a proper fit! Some crampons will not fit certain combinations due to the condition of the boot, crampon, or shape and size relative to the shape and size capabilities of the crampon. The user must confirm proper fit prior to using. Please contact us if you have any questions or would like to discuss this for your specific set-up.
COMPARISON CHART for the K2 and Purple Haze:
Please click to read the PDF document comparing the Forty Below Purple Haze and Forty Below K2 Superlight overboots: Compare PH and K2 2014
Here is a picture of the K2 Superlight™ in the black color, on the website of International Mountain Guides, on the top of Mt. Vinson in Antarctica! Please visit their Vinson page and their website for lots of really cool places they can guide you to use our overboots at https://www.mountainguides.com/vinson.shtml Thanks for recommending our gear!
For more information about all of our different models of overboots, please go to the All About Overboots Section, which is located on our home page. There is an overview of the different models and the boots they go over, and additional information about overboots and insulated boot covers.
Product Photo Gallery:
Put the cursor over the picture to see the heading. Click on the picture to enlarge it and to view the full description. An arrow on the edge of the picture will enable forward and back movement through the set of pictures.
This first gallery is of the Forty Below K2 Superlight overboots being used over double shelled mountaineering boots:
This gallery shows them in use with single mountaineering boots:
Forty Below® K2 Superlight™ overboots :
ORDERING: We will select the proper size for your boots
from the information you provide us in the ordering fill-in boxes above.
Built in the USA! Handcrafted in the USA. We use materials from the USA and our friends from other Countries around the world.
SIZING: XS-XXXL To fit from ladies 4 to mens 16. Fits over “single” or “double shelled” mountaineering boots
OVERBOOT SIZING: Forty Below® Overboots are made with stretchy insulation materials, and have a wide range of different sizes and shapes of boots that a particular overboot model/size can fit. Because of this wide range, we ask that you provide some basic information about your boot and crampon, and then we will select the proper size with that information for you.
COLORS: 4 color choices:
Red gaiter with Black foot.
Red gaiter with Red foot.
Black gaiter with Red foot.
WEIGHT: 1lb 5 oz. (588g) per pair size Medium.