Applicable bolt size: M8; hex socket width: 13mm/0.51" Package Contents: 50 pcs x Dome Bolt Nut Protective Cover. Made of PP plastic, smooth and durable surface, not easy to break. Suitable for hex bolts and nuts, easy to install and remove. It provides good protection for your bolts and nuts and is a great tool to prevent them from rusting and corroding. Due to the measurement manual, the product you receive may have a slight size error Due to different monitors, the product you receive may be slightly different from the picture The quantity of actual delivery is 50 pieces