This super lightweight bag has been updated for 2014 with Hydrophobic down, this flurocarbon free treatment was developed in conjunction with Nikwax and although Hydrophobic Down is not waterproof it dries much faster, absorbs less water and retains loft far better than untreated down. Stuffed with high quality Hydrophobic European goose down and made from stupid light Pertex Quantum GL fabrics the Infinity is designed for those demanding the smallest packsize, minimal weight and top performance. Perfect for ultra lightweight backpacking and mountaineering, ultra marathons and adventure racing. Hand filled in Derbyshire with 300g of 850 fill power white goose down for maximum loft and insulation in a Tapered Mummy shape which is optimised for bags with fill weights between 100 and 600g.This bag has been designed purely for performance with a close fitting and tapered shape with little slack in the inner. The shape of the Trapezoidal internal baffle chamber delivers a very stable structure that results in a consistent distribution of down throughout the bag and the minimal differential cut combine to give a close technical fit. Differential cut is a technology developed by Rab to ensure that the space between the lining and the outer fabric is optimised for the specific filling and fill power. This maximises the potential of the down to loft naturally resulting in greater performance. Both the inner and outer fabrics are Pertex Quantum GL, a superlight fabric that allows the down to reach its maximum loft and molds to your body shape filling up any dead spaces internally. Access is via a 1/2 YKK zip with an anti-snag baffle. An internal shoulder baffle helps to maximise warmth provides. Both the hood and the shoulder baffle have drawcords. Temperature ratings are used to indicate a bags performance but are subjective and can be hugely affected by many factors such as your health and metabolism, how much you have had to eat or drink, how active you have been, humidity and altitude, the type of shelter used and whether you are using a suitable insulating mat. Your sleeping bag is only as good as the mat that’s beneath it, we recommend EXPED mats for comfort and insulation. The Comfort rating indicates the range at which a woman gets a full nights sleep, the Limit of Comfort rating indicates the range at which a man gets a full nights sleep and the Extreme rating indicates a range at which a woman is protected from hypothermia. The Extreme rating is basically a survival rating and it is not advisable to rely on this for general use.