Cumulus is a Polish brand that have produced down products for best part of 30 years. They don’t say much about their products, they let their products do the talking. I was glad to get a hold of the Panyam 450. Cumulus’s spec and description, below, pitches it as a mild winter, late autumn, early spring bag. The 450 has a big brother in the series, the 600 which would push you deeper into winter I would imagine.