This set includes 4 individual skins: 2 for the main buttons and 1 for each side. The pre-cut OP1 skins are designed to provide additional grip while clicking, moving, or lifting the mouse. The main button skins cover the entire button, while the side skins cover the thinnest part of the mouse, stopping where the hump extends in width. By using just the side skins or only the right side skin, you can adjust the shape of the mouse when the hump feels too wide or the grip width feels too thin. The skins have a thickness of 0.5mm and are compatible with all OP1 models. Please keep in mind that if you want to open the mouse with the skins attached, it is important to align them at the lower edge of the top shell and avoid attaching them to the bottom plate.