Design Philosophy The original Pro SL PrimaLoft® Gilet was a game changer, bringing technical hollow fill insulation to the performance cycling market in the form of a versatile, packable gilet. The updated version, the Pro SL PrimaLoft® Gilet II, is even better with improved breathability, stretch and an updated, contemporary design. Lightweight Insulation Two 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® 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.