Review on Quick Release 1 Inch Barbell Clamps - Locking Collar Clips For Standard Bar Weight Plates - Ideal For Fitness Training, Weightlifting, And Bodybuilding By Greententljs by Edward Taylor

I measured my bars before purchasing and they range from 7/8" to 1 & 1/16". These collars fit on my curl bar, my threaded barbell, my 5' barbell, my threaded barbell, my threaded dumbells, and my 400lb capacity barbell. My 800 lb black oxide barbell is too big and they don't fit on that bar, but I have some plates that won't fit on that bar as well. I have no problem using these collars on any bar in the horizontal position. I don't think that I would use them on any bar in any other position like hammer curls or those over head triceps extensions where you hold on to the end of a dumbell, but then again, I wouldn't trust those collars that secure by screwing them into the bar (not the threaded bar type) either (which I have as shown in the pictures). Overall, for keeping weights from sliding off the end of a horizontal bar, these will do the job.if they fit on your bar.