Material and durability - Made of engineering plastics for durability and long life. Design and compatibility - Suitable for use with wiring embedded card holders and frames with a single hole. - The product is designed to protect the brake line where it passes through the frame hole. Size and fit - Embedded length: about 20 mm (0.79 in) - Width: about 8 mm (0.31 in) Function and protection - Effectively protects the brake line from wear caused by the frame hole. - Helps maintain cable integrity in internal routing setups. Package contents - 20 pieces per pack: Bike Brake Shifter Housing Grommets Key benefits - Reduces wear on brake lines at frame entry points - Supports durable, long lasting frame routing - Simple option for protecting internal cable passages Use scenarios - Road bike with internal routing and a single frame hole for brake/shifter housing Install grommets to shield the line as it passes through the frame hole. - Mountain bike with internal routing and a frame hole for housing Use grommets to prevent abrasion where the line enters the frame. - Replacing worn grommets around a frame hole Keeps cables protected and extends the life of the routing setup.