I can tell you that the WM and FF ratings are pretty spot on for a normal sleeper.
If you’re looking at another manufacturer, it’s worth comparing fill weight to a near WM or FF model. If the fill weight is close (and they are using higher end down (850+), then you can be pretty sure they rating will be good to go.
If you’re looking at another manufacturer, it’s worth comparing fill weight to a near WM or FF model. If the fill weight is close (and they are using higher end down (850+), then you can be pretty sure they rating will be good to go.