The North Face Semirectangular Sleeping Bags

How will you be using your liner? 

• For backpackers, a mummy-shaped bag liner helps keep your sleeping bag free of dirt and body oils, helping it last longer. A liner can also be used in place of a sleeping bag in hot climates. 

• For travelers, a rectangular bag liner or travel sheet keeps you separated from bedding of questionable cleanliness or with possible bedbug infestations. 

Which liner material is right for you? 

• Silk: Very lightweight, compact and insulates in cold weather. Absorbent and breathable in warm weather. Price: moderate to expensive. 
• Cotton: Strong, durable and absorbent, but not the lightest or most compact. Price: economical. 
• Fleece and microfleece: Warmer, heavier, soft, moisture-wicking and quick-drying, but the mid- and heavyweight varieties are bulky. Price: moderate. 
• Synthetics (e.g., CoolMax^®): Moisture-wicking, breathable, ideal for humid conditions and stretchy for restless sleepers. Price: moderate. 
• Insulated (e.g., Thermolite^®): Adds enough warmth to greatly extend the range of a lightweight bag. It dries faster than cotton. Price: moderate to expensive. 

Understand temperature ratings
Opt for a sleeping bag with a temperature rating below the lowest nighttime temperature you expect when camping.

Choose a sleeping bag shape
There are four main shapes: rectangular, semirectangular, mummy and double. Generally, you want one that gives you room to stretch.

Select synthetic or down insulation

• Synthetic is more affordable, dries faster and provides warmth when damp.
• Down is lightweight, durable and compresses small.

Consider other features
A waterproof shell, snug-fitting hood, extra zippers and even a stash pocket can add durability, warmth and function.