Unlike other offered here quick release these fit here excellently on 30 dumbbells with thread. The springs are not so stiff and open wide enough, so that they can be comfortable operated with one hand. Nevertheless, they sit bombproof and slip a millimeter. That the standard discs may a little rattle is not bad, because unlike loose Star nuts not turn himself away. Whether the closures also work with 31mm rods or smooth dumbbells, I can not judge. Conclusion: Super investment! The change of the disks work much faster and more comfortable than with the original star nuts.
