Sizing information:

   Overboot Size....................Double Boot Sole Length

 

The 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. 

 Forty Below® overboots 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 (a perfect option is Aquaseal from McNett).  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 are also sold as Tear-Aid Type A patches, and they are indeed very tough and use very strong adhesive.