Like to chase your personal best during your daily workout With the Jack Wolfskin Air Lock Vest nothing could be easier This innovative gilet weighs next to nothing and is super warm and exceptionally breathable In other words it s perfect for winter workouts Everything about this gilet is geared towards keeping weight to a minimum - including the ultra-lightweight PERTEX shell fabric and the innovative mesh fleece NANUK AIR LOCK Q M C consists of hollow fibres with a cross-section that looks like an eight-pointed star The advantage is it weighs less than regular fleece fabrics but provides better insulation The fabric s knitted-like structure makes it extremely breathable It is also air permeable Exactly what you need when you re trying to improve your PB on the fitness trail