For outside utilization, flannel sleeping bag liner should have some properties to support that purpose. People choose sleeping bag because very practical and easy to bring on any journey. You do not need cover or portable mattress to seep. Stretch sleeping bag and put your body inside this thing to enjoy comfortable sleeping. Flannel material for this bag has to be more than normal strong. It can handle risk for being scratch with pebble, ground, and rock. Do not forget to check water and dust resistance. You can predict weather, even in sunny day. Flannel has quality to prevent dust penetration into bag.