CALIDAKA 4pcs Spinlock Collars, Dumbbell Hex Nut, Dumbbell Rod Nut, 1 Inch Standard Barbell Screw Collar, Nonslip Dumbbell Screw Clamps for Dumbell Weight Lifting Fitness Training

Just got these, they fit Bollinger and Yes4All dumbbell handles. They have a slight oder like you smell in the fertilizer department in a home and garden store. I will be using these as lock nuts behind metal screw on collars. The threads are ok, they feel tighter on the Bollinger bars and looser on the Yes4Al bars, but they do tighten up. +

These are great. I have a bunch of different bars and no collars that fit them all. These are loose enough that they fit them all and stay tight.

First, the seller got these to me a day earlier than expected. Second, they actually threaded onto my old school dumbbell handles so for now they get 5 stars. I don't know what name brand my dumbbell handles are, I got them all second hand, but I think some may be CAP. I did try some of CALIDAKA's steel/chrome spin lock collars, but they would not thread on so I returned them. It's weird that their "plastic" spin lock collars work but their steel ones don't. The real question is will they hold up and not break with heavy weight. Since I have a 30-day free return guarantee from Amazon I will be testing the hell out of these and if they pass, I will be purchasing more. Now I mainly use my dumbbells with this type of spin lock collar for bench presses so I will be drop testing these from about 40 inches or so to see if they break. I will update this review with pictures whether they break or not to let others know who are interested in these collars. Stay tuned. UPDATE: They broke after the first drop. Tested these collars the next day from around 40 inches with only 45lbs on the dumbbells and they snapped. Not really surprised because they are plastic, but I was hoping they would last more than one drop test. I even tried NOT to drop them at an angle, just straight down but apparently it didn't matter. From the pictures you can see my "gym" is an outdoor one and the ground was nice and soft, probably even softer than stall mats. I don't know if I would recommend these since they broke so easily, and I don't know how much temperature would affect these mainly the cold. Maybe you could use these on lighter dumbbells but for me, I use all my threaded dumbbells handles on my 40lbs and 50lbs and wanted the extra security of threads, so plates won't accidently fall on my face while pressing. Well, I hope this review will help others interested in these collars.

I bought the four pack. Three work ok, one slips. I use them on dumbbells. I wouldn't use them on very heavy weights.

I am only missing one screw collar from my original set so I bought this pack. I was very disappointed to see that they did not screw on properly. It seems as though the threading is off.

The material is like hard plastic and these feel 3d printed. Thw threads aren't perfect but they work.

Works great

Excellent for the price a little loose but will do the job

1 of the 4 wouldn't screw on to anything that I had, I think the threads were bad. The other 3, however, work great. They screw on easily, and don't move much even when the dumbbell is rotating a lot (such as with finger curls).