The middle-weight bag in the Phoenix range, the Ember 250 is a lightweight and tough sleeping bag for three season camping. The Ember is filled with 250gsm spiral hollowfibre, a lightweight synthetic insulation that weighs only 1.5kg and can be packed into a stuff sack for easy travel.. Comfort and Compression. The mummy shape of the sleeping bag is designed to help trap heat inside, keeping you warm and comfortable throughout the night. This shape also helps to reduce the overall weight and size of the sleeping bag, making it easier to pack and transport. The Phoenix Ember 250 comes with a compression stuff sack, which allows you to pack the sleeping bag down to a smaller size, making it easier to transport. The sleeping bag also features an insulated zip baffle that prevents heat loss through the zipper. This feature helps to keep you warm and comfortable, even in colder weather conditions.. Lightweight. The Ember 250 is a lightweight and tough sleeping bag for two season camping. Th