The Tektro reservoir cap is an essential accessory for hydraulic bicycle brakes, specifically designed for the HD-M390 and HD-T390 models. This cap ensures a secure seal of the brake fluid reservoir, contributing to the optimal functionality of the braking system. Made from high-quality plastic, it offers a durable and reliable solution for those who value safety and performance. The black color seamlessly integrates into the design of the brakes, providing an appealing look. With this reservoir cap, you can ensure that your brakes are always in excellent condition and that the brake fluid is optimally protected. A simple replacement of the cap allows for quick maintenance and contributes to the longevity of your braking system.