- Made from durable, high-quality polypropylene (PP) combined with a sturdy metal hex bolt for long-lasting performance. - Converts your standard 2.5 cm diameter barbell or weightlifting bar into a 5.1 cm barbell, expanding compatibility with a wider range of weight plates and collars. - Perfect for upgrading older barbells, curl bars, and workout machines that require 5.1 cm fittings without replacing the entire bar. - Includes a hex key for easy tightening and loosening of the metal hex nut, ensuring a secure fit during use. - Features a removable end cap to accommodate standard 2.5 cm posts when necessary. - The adapter’s outer diameter is precisely 50 mm, making it fully compatible with any 5.1 cm weight plates and collar systems. Use cases: - Easily update vintage or smaller barbells to fit modern plates without purchasing new equipment. - Adapt curl bars or machine handles to accept larger diameter plates, enhancing workout variety. - Securely connect standard posts with 2.5 cm diameters when smaller weights or attachments are needed. This adapter offers a reliable, practical solution to expand your existing gym equipment’s compatibility and usability while maintaining stability and safety during your workouts.