Tapered sleeping bags are a combination of [mummy] and [rectangular] sleeping bags. They provide a good balance between warmth and mobility inside the bag. These are often used by people who don’t want to be constrained inside a mummy bag, while still wanting to have better insulation than in a rectangular bag.
Many hikers opt for a tapered sleeping bag due to their low weight, small pack size and overall flexibility of use. However, they still don’t perform as well in the cold as a mummy bag does, nor do they offer the same amount of air flow as a rectangular bag.
For more information about what to look for in a sleeping bag, check out our sleeping bags buyers guide!