Stretch inserts

Lid with carabiner

Zippers under the arms for ventilation

They also incorporate a windproof and waterproof HWS (Härkila Weather System) membrane

Sealskinz Upton Waterproof Extreme Cold Weather Puffer Hat Accessory size:L/XL Stretch insertsA fully waterproof, sherpa lined ear warmer cap. Signature Aquasealz technology combines complete waterproofness with breathability, letting excess heat and perspiration escape. A sherpa fleece lining is soft to the touch and insulative. Ear flaps can be fastened up when not in use, offering versatility. Foldable peak design makes packing away in a pocket easy. Further details include a Sealskinz rubber hiking badge on front of hat and an adjustable