Senchi Designs Wren Alpha 60 CrewneckSenchi Designs Wren Alpha 60 Crewneck is an ultralight fleece weighing only 102 g (size M). Made out of Polartec Alpha Direct 60 insulation offering incredible warmth to weight ratio. Streamlined design. Superb insulation when paired with a shell. Very breathable when worn on its own. Senchi Designs Wren Crewneck is made out of Polartec Alpha fleece, renowned for its breathability and insulation capabilities. The Wren Crewneck weighs just 102g (size