The Marmot Pounder Plus 25F PrimaLoft sleeping bag is a lightweight weather-resistant 3-season bag thats so durable you can use it without a tent. Crazy. The Pounders A-Flex construction keeps warm air from escaping and moisture from intruding. Just like your Marmot PrimaLoft gloves, the left-zip Pounder Plus keeps you warm in wet, cold conditions, without bulking up on weight or mass. If youre alpine camping, where the weather can change in an instant, the Pounder Plus is the perfect bag.