These came with my Ziva brand cardio barbell bar. It says they work with a 1 inch bar, but the cardio bar is actually almost 1.2 inches (30mm), which is why these do not work well with the Ziva bar. You have to squeeze them in all the way and even then they do not fit well on the bar to hold the weights securely and in place. Recommend getting Lock Jaw collars to use on your cardio bar instead of these.
