Thanks to technical materials and Rab's knowhow, this jacket is warm for its weight. It is also very packable. The Xenair Alp Light is a good choice for use as a hiker's camp or break jacket, and for general use in many outdoor activities. - Snug fit: especially if between two sizes, choose the bigger one - Light but durable Pertex Quantum surface fabric - High quality PrimaLoft Gold Active+ insulation, 60g/m² at the front, back, top of sleeves and collar, 40g/m² on the sides, underarms and along the spine - The integrated hood is designed to fit under a climbing helmet and has an elastic trim - Two zippered lower pockets - One inner chest pocket which doubles as a stuffsack for the entire jacket - Hem adjustment cord - Center back length 66.5 cm For the technically inclined, the surface fabric has a cfm rating of 2 and the liner fabric lies at 10. What this means is that the outer fabric boasts great wind resistance, while a more airy fabric has been chosen as the liner.