Carhartt Men's Full Swing Washed Duck Insulated Active Jacket

What does the "Full Swing" design mean for arm movement?

Full Swing gear features built-in stretch panels across the shoulders, a bigger bend in the elbows, and specially designed underarms so you can swing a hammer or reach up without the jacket riding up.

How warm is this jacket in freezing temperatures?

It is rated as Level 3 - Warmest by Carhartt, combining a wind-resistant Wind Fighter duck shell with a quilted taffeta lining and 100g insulation to block out extreme winter cold.