Flame and Spark combo for subzero temps
"Great sleeping bag modular solution I've been using for subzero temps (last nights have been down to -3 and I've been in shorts and tshirt, not even dusted off my thermal longjohns yet!). It has been keeping my heat in really well and been warm and 'comfortably' warm to sleep at that. To my mind, the zip is a bit flimsy itself and stitching looks like it will stretch. Zips are a nightmare to repair and constantly getting the material stuck in the zip at night is a real pain. The zip could be left as is if it's like that to be lightweight but a felled strip of cotton down the edges of the zip would solve the issue of material getting stuck in it and it could also be triple stitched to make it durable. Not sure how that would affect heat loss though?? Maybe that extra material would create a bigger area for heat loss"









