Fjallraven says about the Abisko Cool Shirt Short Sleeve
Light and well-ventilated outdoor shirt with short sleeves and regular fit for trekking and travelling in warm climates. Made from lyocell, a viscose-like fibre that effectively wicks away moisture and gives a soft, comfortable feel against the skin. Two chest pockets with flaps and buttons. Gussets under the arms for maximum freedom of movement, and a pair of sewn ventilation holes for extra air circulation.