Mummy shaped sleeping bags are the most common style of sleeping bag you'll come across, and if you want to ensure your child is nice and warm during the night, choosing a mummy shaped sleeping bag for your child is a must. Mummy shaped sleeping bags have a tapered shape, which minimises on empty space inside. When sleeping bags have empty space inside, this creates cold spots within the sleeping bag and doesn't provide as good a level of insulation.
Mummy shaped sleeping bags also hug your body & feature hoods for a more cosy feel & added insulation. Another benefit to mummy shaped sleeping bags compared to rectangle shaped bags is that they use less material due to their tapered shape, this makes them more compact when they are packed into their storage stuff sack, so kids can carry them easily!
I was looking for a bag for my daughter's upcoming trip to Nepal knowing that it would need to be warm and light. Having searched extensively I decided that the Chrysalis 4 fitted the bill. Although we have not been able to test it to its limits yet it has been very snug down to the -2C that we have used it so far. I had read a review that suggested it would require practice to get the bag back into the stuff sack but I found it much easier than suggested.