Bivouac sack, bivy, bivvy, bivi bags and bloody bivvying

"For light-and-fast alpine climbing, our new Hybrid Sleeping Bag embodies a fundamental tenet of minimalism: It eliminates redundancies. Its 850-fill-power Traceable Down, encased in an ultralightweight Pertex® Quantum shell fabric, warms from the torso to the toes. Above, the bag continues with a single layer of whisper-light, windproof nylon fabric—1.2-oz 15-denier 100% nylon ripstop with a DWR (durable water repellent) finish— creating a heat-trapping cocoon when paired with your belay parka. The half-zip saves precious weight, and drawcords atop the insulated portion and at the hood help seal-in warmth, preserving your energy for the summit push.

Ultralightweight Pertex Quantum® shell uses interlocking Y-shaped nylon fibers to enhance the performance of the DWR (durable water repellent) finish
Featherweight 100% nylon ripstop liner with a DWR (durable water repellent) finish
850-fill-power Traceable Down (European goose down traced from parent farm to apparel factory to help ensure the birds that supply it are not force-fed or live-plucked)
Paired with a high-alpine insulated jacket or parka, the hybrid sleeping bag becomes an ultralight backcountry sleep system
Custom footbox pattern eliminates dead space and bulk, maximizes warmth and affords ample room for movement
Adjustable drawcord at waist for sealing in warmth
Ultralight stuffsack included
Shell: 0.85-oz 15-denier 100% nylon ripstop Pertex Quantum® built with Y-shaped filament technology; with a DWR (durable water repellent) finish. Fabric is bluesign® approved. Liner: 1.2-oz 15-denier 100% nylon ripstop with a DWR (durable water repellent) finish. Insulation: 850-fill-power Traceable Down (European goose down traced from parent farm to apparel factory to help ensure the birds that supply it are not force-fed or live-plucked)
490 g (17.3 oz)
Made in China."

So about the weight of a heavier bivvy but insulated with down. Interesting.