The Arc'Teryx Men's Gore-Tex Insulated Mid Liner is an insulated liner for the Men's Acrux2 FL and Men's Bora2 Mid. The insulated liner allows you to go from a spring/summer boot to a fall/winter boot with toasty warm toes. The 2 layer stretch nylon mono-mesh with insulative EVA foam core wraps the foot and stretch Gore-TEX laminate is waterproof and breathable for unsavory weather. The rubberized textile at the bottom at the bootie allows you to wear them around camp for a comfier foot after a long day of hiking. Features of the Arcteryx Men's Gore-Tex Insulated Mid Liner Removable waterproof/breathable stretch Gore-Tex liners have adaptive Fit that conforms to the foot Lower height, lighter weight liner provides quick-dry summer comfort Higher, more insulated liner suits winter conditions, Snow or cold temperatures Removable, 2 layer stretch nylon mono-mesh with insulative EVA foam core, Stretch Gore-Tex laminate to 100% of liner height Front and rear pull loops to allow you to put shoe/boot on more easily Tongue free liner ensures a larger breathable surface Area and increased waterproof coverage Stetchable Gore-Tex liner Arcteryx adaptive Fit utilizes an independent liner that conforms to the foot for a custom Fit with no pressure points Completely removable, interchangeable liner for improved washability, dry-ability and extends use and climate adaptability Insulated mid-cut liner for Snow or cold temperatures 2 Layer stretch Nylon monomesh, Stretch Gore-Tex with air permeable EVA foam core