Very practical compared to screwing and unscrewing.
It doesn't have absolute grip (around 90-95%), but in any case it does its job.

These particular safety collars are among the best options currently available on the market. Personally, I managed to solve a long-standing problem I had with screw-on dumbbells, which often loosened during exercise, causing both the plates and the collars themselves to rotate. By using the safety collar in combination with the screw-on collar, dumbbell exercises can now be performed with complete safety, even with quite a lot of weight. Although the safety collar alone is not designed to hold very heavy loads, its combined use with the screw-on collar offers excellent stability and reliability. This is a particularly useful solution for anyone who wants to exercise with greater safety and confidence.

I have been using them for over 1.5 years and they are very good, they haven't come off the dumbbell or the bar even once

Pros: lightweight, fast to fasten and unfasten. Holds as needed to prevent heavy weights from easily shifting on the bar.
Cons: Cannot hold a lot of weight in a vertical position - obvious because its construction is lightweight and made of plastic material. For quick tightening and loosening on a bar for horizontal use, it is exactly what is needed. I use it for bench press exercises and on a crooked bar.

They hold the discs well, which I had some doubts about due to the shape of the F28 bars, and so far they haven't come off the regular bars, but also small bars, although I haven't tried weights over 90 kilograms. If they were a little tighter, they would be perfect. 4.5 stars from me

The best thing about these collars, everyone should buy them for the bar, as they greatly facilitate the process and are very tight, without fear of the plates coming off.

It does the job for which it was designed. Some of them I have had for a year and they haven't loosened at all, some are new and there is no difference from the older ones. Very satisfied. For exercises that require standing dumbbells - as Ziiiv says - indeed, from a certain weight and above they start to give in, but the same would happen with any collar, except for the screw-on ones. They are not designed for this use.

As long as the dumbbell is parallel to the ground, it is very good. However, when performing exercises that require the dumbbell to be upright, with more than a certain weight, they start to give way, with the result being dangerous. It is not recommended for exercises with upright dumbbells (e.g. chest pullover).

The strength that holds the plates is moderate, there is a fear that they might come off and loosen even more over time. Not suitable for heavy weights

Very good quality that stabilizes the discs on the dumbbells/bar without needing constant intervention like with screw-on collars. After 3 months of use, they haven't loosened. I would buy them again!