The Shimano SM-BH90 2.1mm Bore Olive & Connector Insert helps you securely connect a hydraulic brake hose to a Shimano brake lever or calliper. It uses a 2.1 mm bore olive and precision-machined connector insert that compress into the hose during installation to form a tight hydraulic seal.Key Features:2.1mm Bore SM-BH90 Olive Design: The olive is sized specifically for Shimano SM-BH90 hydraulic brake hoses with a 2.1 mm internal bore, allowing the soft metal olive to compress around the hose when tightened so you achieve a secure seal that prevents hydraulic fluid leaks and maintains consistent brake pressure.Precision Connector Insert Construction: The connector insert fits inside the brake hose and supports the inner wall of the hose during tightening, keeping the hose round and stable so the olive compresses correctly which helps you achieve a reliable connection and predictable brake performance.Genuine Shimano Replacement Specification: Manufactured to Shimano s original equipment standards and listed as part number 2 in the SM-BH90 hose assembly diagram, this component provides exact dimensional compatibility so you can restore a worn or damaged hose connection and return your braking system to proper working condition.You maintain consistent hydraulic brake performance when your hose fittings seal correctly and hold pressure. This olive and connector insert allow you to rebuild or install a Shimano SM-BH90 brake hose with the correct internal support and sealing components. Keeping one in your workshop or toolbox is a practical choice when servicing Shimano hydraulic brake systems.