The Nemo Riff 15 Sleeping Bag is a down filled bag in a unique spoon shape. The spoon shape provides added room at the elbows and knees, making side sleeping comfortable.
Nemo says:
Seventy percent of people sleep on their side, but mummy bags are not designed to accommodate this. With a unique Spoon™ shape adding room at the elbows and knees, the Riff™ is a three-season down men’s backpacking bag that is designed for side sleepers, and allows you to shift positions throughout the night.
This popular bag is loaded with features, including Thermo Gills™ that help regulate temperature during the night, Blanket Fold™ that provides tucked-in comfort, and a waterproof/breathable footbox to withstand tent condensation. Zip together with the women's Jam™ for a double bag. This bag is a versatile superstar for everything from backpacking to car camping.
Finally a truly comfortable sleeping bag for side sleepers. The Nemo Riff 15 Sleeping Bag has been designed in a 'spoon' shape (I would describe it more as a number 8) so its wider at the elbows and knees, meaning you can toss and turn as much as you want, without the bag restricting you.
What also makes it stand out is that it looks like it has 2 slits down the center of the bag, these are what Nemo call Thermo Grills. They unzip to let warm air out if you get too hot at night, allowing you to vent body heat without letting cold drafts in.
Another feature it has that is quite unique to Nemo bags, is the Blanket Fold. Like a comforter at home, the blanket fold gives some extra material to snuggle around your face and helps to control temperature.
These are just a few of many, well-thought-out features that this bag has to offer. If you're looking to share the comfort with your lady friend, the bag can also be zipped together with the women's Jam sleeping bags.