Had it down to 3 degrees F on top of a thermarest…
Fill: Polarguard 3D
Weight: 3lb 14oz
Price Paid: $140
Had it down to 3 degrees F on top of a thermarest guidelite with a fleece sweatshirt and tights on, and was still snug as a bug (even had to open the foot vent). Also had it partially soaked in 30 degree weather and was still able to sleep fairly comfortably...thank god for synthetic fill.