The Thermarest Boost 650 32F/0C is a premium three-season sleeping bag engineered for versatile backcountry comfort. Its standout feature is the dual-sided expansion system, providing an additional 25 centimetres of internal space for active sleepers. Utilising 650-fill Nikwax Hydrophobic Down, it maintains loft in wet conditions without the use of harmful PFCs. This model is an excellent choice for professional buyers seeking customisable warmth and reliable performance.