If you're graduating onto buying your first down sleeping bag, the Rab Ascent 500 is a good place to start.
The Pertex® Microlight fabric, used both inside and out is silky to the touch, but hard wearing and close woven to prevent down escaping. The Ascent 500 gets its name from the 500 grams of high lofting (650FP) European Duck Down that has been carefully spread throughout the trapezoidal baffled construction of the bag.
The down fill has been hydrophobically treated to help maintain its heat retention properties even in damp conditions.
If you've ever woken in the night, desperate for the toilet you'll know the exasperation of getting the sleeping bag zipper stuck as you try to wriggle out. To avoid this Rab have fitted anti-snag webbing tape along the whole of the ¾ length YKK zip.