Made of high-density foam, degbootcap (R) keeps skiers ' feet 20 deg F warmer without batteries or other electronics. The brainchild of ski industry veterans, degbootcap (R) adheres directly to the outside of a ski boot 's toe box, providing instant insulation and warmth. A solution so simple, we were surprised it hadn 't been invented already! bootcap Bootcap 2.0 | Khaki | Christy Sports