These are the stitched compartments that hold the down.
This measures the quality and "loft" (fluffiness) of the down. 550–650 FP: Good for everyday casual wear and commuting. how to buy a good down jacket
Uses internal fabric walls to allow the down to loft fully, eliminating cold spots. These are warmer but bulkier. These are the stitched compartments that hold the down
The performance of a down jacket is primarily determined by two key metrics: Uses internal fabric walls to allow the down
Premium, expedition-level quality providing maximum warmth with minimal weight and high compressibility.
A "good" jacket should include functional details that enhance its performance: Down Clothing Buying Guide - Mountain Equipment
While fill power tells you the quality , fill weight tells you the quantity of down. A jacket with high fill power but very low fill weight (like an ultralight layer) may be less warm than a heavy "parka" with a lower fill power.