Sleeping bags come in a wide range of shapes, but most can be broken down into two basic categories: rectangular sleeping bags and mummy-style sleeping bags. Rectangular bags are larger and often heavier. They’re good for car camping and are better choices for anyone who likes to have more space.
Mummy-style sleeping bags are more form-fitted and often offer better insulation in colder weather. Their close fit does a great job heaping heat from escaping. The only disadvantage is that some people, especially those with a huskier build, may find them constricting.