Great cold weather bag - Marmot Lithium Sleeping Bag

I tested the Lithium against the Marmot Never Summer for my early and late season tent camping needs supporting trail work events. I already owned a Nemo Nocturne 15. I hadn't tested that one to determine how close to 15 degrees it would go and learned the hard way that its threshold was closer to 30 after two weekend uses in Wyoming and Colorado. In my test of the Lithium and Never Summer, the Lithium was superb and warranted the higher price point. For the test, I used my Big Agnes 3 season tent and Exped Downmat UL Winter pad, and wore Smartwool 250 baselayer and Darn Tough socks. At 12 degrees with 25+ MPH winds, I slept well with no drafts through the zippers (right and left side), hood, and draft collars. Around 0200, I was so warm I shed the socks and unsynched the torso draft collar. Great bag. Will test the upper temperature limits in the spring/early summer. Definitely recommend.