The bells are rather large — no tapering as with Bowflex — and I do wish I could add weight in 2-1/2 lb increments, at least up to 25 lbs, as with Bowflex, but as the Bowflex bar remains the same length, no matter how many weights are on it while the CF bars grow incrementally with the number of 5-lb plates attached. For lower weight exercises such as for my shoulders (after having had 4 rotator cuff surgeries, I use a set of non adjustable dumbbells and I no longer do ab exercises while hanging from a chin-up bar. Exercise is addictive. My last ortho surgeon, a "sports medicine" doctor, admitted that after breaking his arm, he was back doing curls after a week and broke the arm again, proving that even medical doctors can be as stupid as the next guy. His office is always filled with patients — most of them, these days, young women. Dumbbells can be especially dangerous, as unlike with a barbell, your arms cannot train or help each other. So, it is important to have a good set of dumbbells, and keeping in mind the dangers, unless you have the room and want to invest in a set of single dumbbells, these from Core Fitness may suit your needs and fancy. As with all good tool, you must them with respect in hopes of not dropping them and damaging the mechanism. But let's see how long they last.
Update: NOT QUITE A YEAR. One the set did not pick up the 5 lbs weight and now will not go back into the rack. Unless I can figure our how the mechanism works and fix it, I have just thrown about several hundred bucks. Not sure if there is a warranty. Quit a SCARE. But I figured out how the mechanism worked and solved the problem. Now can use my dumbbells again. BUT BEWARE! I was on my own.
So others who purchase this set don't get discouraged and toss the out or get frustrated and damaged the mechanism, just remove the 5# weights from the cradle, reinsert the empty bars correctly, and twist. That will release the dumbbell mechanism in the dumbbell and allow you to twist it until all the weights are off. Then reload the 5# endplates and — voila! — you are back in business.
UPDATE: Had these since July 2019 — almost three years — and used them regularly 3-days a week. Still just as good as new. Great investment. I've been exercising with weights since I bolstered my Charles Atlas exercises with those of Mr. America (1947) Steve Reeves, and I can tell you that these are the greatest development since Atlas introduced the "dynamic tension" for fast and convenient and cheap muscle building.
Update: 6/24/22. Still going like the Energizer Bunny! I have to admit, I dropped one and thought it broke. But I fixed it in minutes by taking it back to no plates, then adding plates. Contrary to some raters, I would rate these as tops. As for the company that makes them, I can't say, as I have no complaints. Nor can I make a comparison, with similar dumbbells by other makers. All I know is these do everything claimed and more.

Nice weights – I've had adjustables before, but these work really well (easy to add the plates) and feel good – like regular dumbbells.

The Core Fitness® Adjustable Dumbbell Weight Set is a smart, space-saving solution for anyone who wants the flexibility of multiple dumbbells without the clutter of a full rack. Designed for convenience and ease of use, this set is especially appealing for home gym owners and busy lifters.
One of the standout features is how quickly the weight adjusts. With a simple turn of the handle, you can change resistance in seconds, which makes supersets, drop sets, and circuit training far more efficient. The compact design keeps your workout area clean and organized, and the included cradle makes storage easy.
The dumbbells feel solid and well-balanced in hand, with a comfortable grip that works for both strength training and higher-rep workouts. They’re versatile enough for everything from bicep curls and presses to lunges and rows, making them a great all-in-one option.
On the downside, the maximum weight may feel limiting for advanced lifters who regularly train very heavy, and the premium design comes at a higher price point than traditional plate-loaded dumbbells. However, for most users, the convenience and build quality more than justify the cost.
**Overall**, the Dumbbell Weight Set is a reliable, user-friendly choice for home workouts. If you value quick weight changes, durability, and saving space, this set is a strong investment that can grow with your fitness routine. 💪