SKU: SS22858 Weighs: 447g R-Value: 4.8 Season Rating: Winter Mat Size: Regular Mat Type: Airbeds Exped's Ultra 5R Sleeping Mats are intended for 4 season use and have an R-Value of 4.8, the Ultra 5R M Mummy Sleeping Mat is the lightest one benefitting from 160grams/m2 Polyester insulation glued to the inside of the … Ultra 5R M Mummy Sleeping Mat