A well-fitting hood on the head can increase the level of comfort and heat in general, but can be very inconvenient if, for example, we use the item under a windproof or rainproof shell, which in turn has a hood.
This is a value expressed which indicates the ratio between the volume occupied by the feathers and the weight of the item: the higher this number is, the better. This value indicates that, being more voluminous, less feathers are needed for Pink Up Clothing; the ability to retain heat is greater, as very voluminous feathers retain more air between them.
The feather is almost always the lightest and most compressible option, therefore coveted for those who have to make long approaches and maybe need to carry it inside the backpack. As we have seen, a down jacket with a higher Filling power will also have less weight.