Packs small, thin, works darn good w/in designed temps. just wear clothes in it if temps goto low - Marmot Nanowave 45 Sleeping Bag

Been using this since 2014, on top of a Big Agnes AirPad. The combo works great. Only once did temps give me concern. Places I go with it seldom delow the 45 F rating. One time though a cold layer of fog rolled in. That time I had to put on a pair of base layers and socks, but usually in the typical SoCal chapparal forest I go to I'm just wearing like a motoX jersey, and the soft hikers boxer briefs undergarment. The bivvy is nicely thin and light and rolls up quite easy. Easy to wash when you get home as well.