The Sleepline 250 Double Envelope sleeping bag is a classically designed 2 season bag with enough room for 2 people. It's the perfect go-to sleeping bag for family camping, caravanning & festivals.. Unrivalled Construction. The Highlander Sleepline 250 Double Sleeping Bag is a sleeping bag designed for two people. It has a temperature rating suited for use in cool to mild weather conditions. The sleeping bag is filled with 250g/m² of polyester hollow fibre insulation, which provides warmth and comfort throughout the night. The outer shell of the sleeping bag is made from durable polyester fabric, and the inner lining is made from soft-touch brushed polyester. The sleeping bag also features a two-way zipper, which allows for easy access and ventilation.. Compared to other Double Bags. The Highlander Sleepline 250 is priced lower than most comparable double sleeping bags on the market, making it a more affordable option without skimping on quality or durability. The Sleepline 250 is rela