Spring Collar Olympic serves as a way to secure weight plates on an adjustable dumbbell or barbell. It is suitable for Olympic bars (50 mm). The simple spring mechanism with two grips allows you to secure the weight plates on the barbell or dumbbell. If you slightly press the grips together, the inner diameter of the spring will widen. After you slide the spring clip onto the bar and release the pressed grips, the sprig will tightly attach itself to the bar and secure the weight plates so that they cannot move.