Fitted or oversize, with a cable-knit design or equipped with a handy zipper, turtleneck sweaters are an essential item in a man’s wardrobe. Styles made with thin knits, in either wool or cashmere in white, beige and gray, pair well with jackets and suits for elegant looks. More relaxed sweaters decorated with patterns are great for creating everyday or weekend-friendly outfits. Here are the designer must-haves from the best brands.