The Lathrop & Sons Synergy Insole is manufactured using a soft medical-grade polymer and meticulously covered with an ultra-soft 4-way stretch red kinetic cover. Perfect for high-impact sports and strenuous activities L&S Synergy Increases comfort, reduces pain, and protects from hot spots and blisters. Now everyone can upgrade their boots. Sizing GuideSmall 8-10Medium 11-13Large 14-16 FeaturesMedical Grade PolymerUltra Soft 4-Way Stretch Kinetic CoverBatwing Arch SupportEnergy Transfer BridgeDecelerating BeadsDeep Heel CupMetatarsal Pads