25mm 1inch Gym Barbell Dumbbell Spring Collars Metal Clips Lock Weight Bar Clamp

They will fit all standard 1 "hole (2.5 cm) weight lifting barbells or dumbbell bars. Prevent the plate weight from sliding off the rod. Circlip: 2.5cm small circlip (threaded rod). It is made of solid steel and rubber support handle.

eBay