Tank top are upper garments worn like camisole, sleeves are worn for inner like if you are wearing a blouse, polo, shirt, and jacket. It is plain and simple. While the vest is a sleeveless cloth worn outside of shirts, polo, blouse and inner of the men's coat. Usually vest are deep V shape cut sleeves cloth. These are being used as a uniform to other companies, with logo, outside pockets, and zipper or buttons in front.