OMM Mountain Core 250 Sleeping Bag Keeping you comfortable and cosy through the night, the Mountain Core 250 Sleeping Bag is a lightweight sleep system that ensures you remain warm. The Mountain Core 250 Sleeping Bag is a great companion for your outdoor sleeping arrangements, due to its cosy, warm and breathable material construction. Utilising a thick PrimaLoft ACTIVE lining, the Mountain Core 250 has an open fleece feel with the additional benefit of providing an exceptional warmth-to-weight ratio. These materials provide you with excellent next-to-skin sensations, ensuring comfort is constant, whilst also keeping you warm during the night. The materials have moisture-wicking properties to prevent an uncomfortable build-up of heat and moisture, therefore keeping you dry. Providing you with the perfect microclimate, the PrimaLoft ACTIVE also allows for excellent airflow, to further prevent you from becoming too hot, whilst simultaneously providing excellent insulat