The TANDEMKROSS Challenger Bolt Knob is a high-quality aftermarket upgrade designed for improved handling of your firearm. This particular model, TK42N0580BLK1, features a unique ergonomic design that enhances grip and control when operating the bolt. The installation of this bolt knob can provide a more tactile experience, allowing for quicker and smoother bolt manipulation.Key FeaturesErgonomic Design: The bolt knob features a design that improves grip and control during operation.