Wax
To prevent slipping on the board, wax is used on the top of the board. The wax prevents you from slipping off the board when you paddle and prevents you from slipping when you stand up. The hardness of the wax varies depending on the water and air temperature. In cold water, you need a soft wax and in warm water, a hard wax is required. You should always put a hard wax (base coat) on the bottom, the hard wax creates a foundation that allows the softer wax to stay on the board.
