The Rab Mummy Silk liner is sure to add extra comfort, warmth and protect your bag. Chinese silk is one of the lightest natural fibres, giving great warmth for weight, as well as a bit of luxury! A liner also keeps your sleeping bag cleaner for longer, saving on the need to wash it so often. The liner is mostly rectangular with a slight taper to reduce excess fabric in the bottom corners. The taper is not too agressive in order that all feet can fit in comfortably.