We built the Regulator Mitten to keep the frost at bay, made with insulated construction and HydroBlock(R) Pro 10k/10k waterproof/breathable fabric. By grouping the fingers together, the Regulator Mitten provides extra warmth when the temperature starts dropping. For those extra frigid days, we've also built these mittens with fleece lining and included a zipper heater pack pocket. Fit & Design: Insulated Waterproof Breathable Fleece-lined Heater pack pocket Technology: HydroBlock(R) Pro 10k/10k waterproof/breathable fabric Additional Details: