It starts with a heat-moldable liner made of open-cell Intuition® foam - allowing the liner to form to the exact shape of your leg, ankle, and foot for superior fit, warmth, and comfort. The secret to the award-winning fit is our Conda™ liner lacing system. Powered by a BOA® Fit System dial, this forgiving and adjustable harness is designed to pull the user's heel into the boot's heel pocket. This urethane-based harness hugs your ankle and flexes naturally.