There are two main types of pockets: flat pockets and expandable pockets. Flat pockets are not expandable and can hold slim items like notebooks or phones. Expandable pockets, like bellows or baseball pockets, have pleats or tucks that allow them to expand and hold bulkier items like glasses or wallets. Some other pocket types include slash pockets with a window opening, side seam pockets sewn into the garment seams above the hip, and trouser or hip pockets drafted to the front of pants or skirts.