Design PhilosophyBuilding on the success of the original Pro SL PrimaLoft® Jacket, this updated version has improved breathability and stretch panels for an even better fit.Lightweight InsulationTwo different types of PrimaLoft® fill have been used. 80g of PrimaLoft® Gold has been used on the front torso, maximising insulation exactly where you need it most. 60g of PrimaLoft® Gold fill has been used on the sleeves, cutting down on bulk and 60g of PrimaLoft® Silver Active has been used on the back, giving improved breathability and accomodating some stretch to create a great fitting garment.PrimaLoft® Insulation PrimaLoft® insulation boasts an exceptional warmth to weight ratio, tiny pack size, extremely breathable construction and is highly water resistant making it a tremendously versatile performance insulator.