Our Blood Line apparels are designed to be layered for quick adapting to your changes in activities & habitats. We know that we don't want a $600 jacket, just to use it for shredding. Our tech streetwear can be worn individually or multi-layered, to function just as good or even better, by smart layering. The Sleeping Bag Hoodie is our final insulating layer (Sealing layer), to be worn over most of our Tech Hoodies. Hence, it is patterned a bit roomier. If you are planning to wear this mostly on the streets and want the slimmer fitting, go size down than your normal size. (For instance, lot of us wear this on our bare skin at the waters in the summer time.) If you plan to wear this in harsh colder environments, go with your regular size and it will have ample enough comfort room for smart layering. Most of us have this compacted down in the pouch and always have it in our shred bag, for that time when you need that insulation sealing - in style.