The new and improved Nebula Pro Jacket from Rab is the ultimate hardworking synthetic insulation that you can stow away in a pack and wear anywhere. It is engineered with all-new, high-lofting, synthetic PrimaLoft Silver RISE insulation, that provides instant warmth and protection ...The new and improved Nebula Pro Jacket from Rab is the ultimate hardworking synthetic insulation that you can stow away in a pack and wear anywhere. It is engineered with all-new, high-lofting, synthetic PrimaLoft Silver RISE insulation, that provides instant warmth and protection against cold and damp conditions.