The north faces thermoball full zip jacket utilises the breakthrough alternative to down for unwavering warmth even when wet thermoball insulation uses clusters of primaloft synthetic insulation to trap air in small pockets for tremendous warmth equivalent to 600 fill goose down the thermoball full zip is lightweight packable and unlike regular down it retains warmth in wet conditions an agile choice for any adventureactivitywalking hiking snowsports casualcolour swatchblackfasten