Abstract: A removable insole for insertion into footwear, includes a forefoot portion extending at least to metatarsals of a foot, with a second recess at an undersurface thereof with a plurality of cylindrical protuberances in the recess; a cupped heel portion including a relatively flat central portion and a sloped side wall surrounding the relatively flat central portion; a mid-foot portion connecting together the forefoot portion and the heel portion, the mid-foot portion including a medial arch portion defined by an extension of the sloped side wall, the sloped side wall extends to lateral and medial sides of the mid-foot portion, and the forefoot portion, heel portion and mid-foot portion formed from a unitary resilient material; a shell that extends along an underside of the insole, the medial arch portion and the sloped side wall at the heel portion and the mid-foot portion, the shell having an opening beneath the relatively flat central portion of the cupped heel portion and a gap at a rearmost end of the shel