Luxebell Thumbscrew/ Thumb Aluminum Stainless Screw Set for Gopro Hd Hero4,Hero3+,Hero3,Hero2 & Hero Camera (Blue) These screws are the same shape and can be used in the exact same way as the original GoPro plastic screws. The rubber washer provides a cushion between the screw and the mount/case. This will help prevent damage or abrasions and will make the screws easier to tighten or remove. If you prefer to use the screws without the washer, simply remove the acorn nut and roll the washer off of the screw. Billet Aluminum Thumbscrew, High quality stainless Steel Acorn Nut. Help you to easily tighten and loosen screws between Gopro mount and camera, and a O-ring helps to prevent camera from abrasion yet not essential for every buyer. 100% brand new and high quality.