With 5mm thick Aerospring foam and a flexible heel cradle, the Superfeet FLEXmax insoles offer long-lasting comfort for roomy footwear. The Superfeet FLEX series of insoles offer an excellent introduction to the Superfeet experience because they give you the comfort that you need while still allowing your boot to flex and perform it's best. If you have high arches and a rather deep heel cup them the FLEXmax is the choice for you.Features:Deep Heel Cup - Wide & Deep Heel CupMoisturewick w/ Odor Control - Top Later delivers odor controlAerospring Foam - Durable viscoelastic closed-cell foam impact to deliver long-lasting comfortFlexible Comfort Cradle - Horseshoe shaped heel cup that provides structure and stabilityVentilated Forefoot - Improves Air CirculationPlease keep in mind, for sanitation reasons, we can no longer accept returns for any used Insoles. Chat with one of our Gear Experts if you have any specific sizing concerns pre-purchase.