Forma Phantom Flow Boots The Forma Phantom Flow Boots provide superior ventilation through a ventilated polyester construction. The rear spine system controls flex and torsion while a velcro and zipper closure keeps the Phantom secured. Air mesh lining and a replaceable foot bed with an air pump system keep the interior fresh. Features: Ventilated polyester upper Custom fit dual density rubber sole Tested and certified to EN 13634:2010 standards Rear spine system for controlled flex and torsion Injected and molded synthetic protectors Polyurethane shifter reinforcement Air intakes for ventilation Velcro and zipper closure Lateral lever closure Shock absorbing insert in the heel Innovative front cambric system with skeletal design that provides more flexibility and protection Air mesh lining Polyurethane nylon reinforcements Soft polymer cushioning with memory foam TPU Dual Flex with shock absorbing felt midsole Replaceable foot bed with A.P.S. (Air Pump System)