Scholl Gel Activ Open Shoes Insoles Scholl Gel Activ Open Shoes Insoles provide invisible comfort for open sandals and heels. Made from transparent soft gel, the ultra thin design ensures that they are discreetly hidden when worn in open shoes and does not crowd the toes while still cushioning the ball of the foot from pressure. The underneath is sticky to ensure that the insoles stay firmly in place. Scholl Gel Activ Open Shoes Insoles have been designed and assessed in consultation with foot care specialists.