Thought these sweaters were just for jogging? Think again. Half-zip activewear is trending right now and you'll regret missing out. Choose from slim-fit and looser styles by Napapijri, LNDR, Pink Pony and more to find your favorite and wear it with a denim skirt and boots for an Instagram-ready look. Whether you go for simple zips or trendy ring-pull styles, make sure you have at least one in your collection this season.