Made to withstand the abuse of repetitive, fast-paced workouts, Olympic weight lifting, and power lifting. Constructed with bright zinc shaft steel rated at 155k PSI to provide the ultimate flexibility and rigidity. The medium knurl provides gripping security, but is also a comfortable surface for multiple repetitions. International Weightlifting Federation spaced rings, snap ring design, and heavy duty bushing that delivers unbelievably fast spin with little to no maintenance. Made in the USA (lifetime limited warranty).