Pro-Bolt Alloy Push In Button Inserts are ideal for covering bolts, keeping out the dirt or for an effective colour contrast. Push-in buttons can be used in conjunction with Cup Washers and fit into the head of a Parallel Allen Head Bolt, they are held in place with the supplied rubber 'O' ring. Material specification: 7075T73 Anodising: Chemically brightened and colour anodised to between 8 and 12 microns thick Weight: 60% lighter than stainless steel - 40% lighter than titanium. Corrosion: Resistant to saltwater, road film and mild acids. Application: Aluminium is suitable for use in all non-safety critical areas. Aluminium is not suitable for any stress area applications. Size refers to the thread diameter of the bolt. Sold Individually.