Sleeping bag liner has two layers of cotton jersey bonded together with a waterproof membrane in the middle. So it is just ‘one’ piece of fabric as opposed to the quilted version which has two pieces of fabric top and bottom. Waterproof products will never be as thin as a cotton sheet – as they need waterproof membranes. This liner is about the weight of a flannelette sheet. More Details This liner fits inside most Child standard sleeping bags (170cm x 70cm) and there is a side opening to make it easy to get in and out of. The top and bottom are waterproof so if your child wets up, or ‘wraps themselves around’ it will still protect the sleeping bag. An added benefit is that the waterproof layer will stop ground moisture from reaching the sleeper. Simply sleep inside this liner to be assured of a night of no leaking, even if an accident does occur. Our Sleeping Bag Liners have been third party tested and certified by Green Leaf to ensure they are environmentally sustainable and non toxic. Care & Composition Composition: Two layers of 100% cotton jersey with a thin laminated polyurethane layer for waterproofing. Care instructions: Please wash separately prior to use as this will soften the fabric. Cold or warm machine wash only. After washing you may have to turn inside out and spin again to lose excess water that may beocme trapped inside. Line dry or tumble dry on a low setting. Do not iron or dry clean. Do not use with bleach or fabric softener. Do not use with an electric blanket.