A gym jacket is a lightweight, breathable upper garment designed for workout sessions and athletic activities. It typically features a full-zip front for easy wear, made from moisture-wicking fabrics like polyester or spandex to keep the wearer dry. The design often includes stretchable panels or mesh inserts for ventilation and mobility, with a fitted or slightly loose cut for comfort. Available in vibrant or team colors with sporty patterns, it may have pockets and elastic cuffs. Gym jackets are ideal for warm-ups, cool-downs, or light exercise.