The Powerstep Ultrastretch Night Sock contains ultra-soft material, a comfortable sleeve design and an adjustable dorsiflexion strap which gently pulls the toes to stretch the calf muscle and soft tissues of the foot and ankle. By providing a gentle and effective stretch and keeping the foot in a neutral position, the UltraStretch helps alleviate theheel pain associated with common overuse injuries such as Plantar Fasciitis and Achiles Tendonitis when taking those morning steps.