If you want to get the best of your transport, try this.

Actually no, or at least I don't think so.
What I envisage is say the CD player just gliding along on the bearings until it slides off. The bearings do not move anywhere, just rotate in the bottom housing allowing whatever is on top to move easily and readily!

It is now just a variation on what we use to move heavy equipment around in factories.

I am a more confused as to how they can work without a top piece?

Well, they are cup shaped. It could be that the photos don’t depict how deep the cups are. They are convex. And as I mentioned, the older site showed top halves that matched the bottom halves with the ball bearing in between. If you are concerned about it rolling up, over and out of the cup’s lip, then you could ask for a top halve to ease your worries.

All the best,
Nonoise

Nope
Not worried at all about the bearing rolling out of the cup, think you may be missing my point.
With say all 3 bearings freely spinning in the bottom cup bases, anything placed on top WILL slide on those bearings very easily.
At least that is my take on it from an engineering point of view.

@uberwaltz I know what you mean.I tried an off brand similar to rollerbearings and the component did actually slide right off of the footers.It was a cheap "knock off" product though.The rollerbearings must be a much better design I'm assuming since so many people use and recommend them.
I have my components on sand platforms.

Final Daruma were the first to use the ball bearing type footers, they consisted of top and bottom cup with ball in the middle, the last edition was the Final Daruma 11/111 retailed for around 199 US Dollars which i have 2 sets of.
Symposium products are way over priced as are Stillpoints.
Townshend Audio Seismic Isolation Pods retail 99 gbp each are a spring based isolation footer and are much better than Symposium Rollerblocks and the Final Darumas. And as GK states cover the six seismic isolation vibrations, backwards, forwards, left, right, up and down.
Herbies Audio Labs Tenderfeet perform nearly as good as Townshend Seismic Pods at a much lower price and the component sits very tightly in place so you could never push it off.
If you want to hear your component at its best without the character/colouration of bearings buy Townshend Audio Seismic Isolation Pods. Max Townshend was one of the first engineers that understood the damaging effects of vibration ie The Townshend Seismic Sink hes latest Seismic Isolation products address the 6 Seismic type vibrations better ie the Seismic Pods, Seismic Platforms and Seismic Podiums. If you want the best bang for your buck then its the Seismic Podiums you need, they isolate your loudspeakers stopping unwanted vibration from travelling threw the floor and up into your rack and into sensitive equipment. and back up into the speakers also. Checkout on youtube Max Townshend explaining the damaging effects of spikes.
I have tried Stillpoints ultra SS and ultra 5s to isolate all components and speakers the overall cost was nearly 20,000 us dollars,
Symposium Rollerblocks isolating the hole system including speakers was approx 10,000 US Dollars.
Townshend Audio Seismic Isolation isolating all components and speakers Seismic Pods and Seismic Podiums was 5000 US Dollars.
Herbies Audio Labs isolating components and speakers Tenderfeet, Giant Roller Gliders and Supersonic Stabilisers was under 1000 Us Dollars.
Townshend Seismic Isolation was the most effective especially the Seismic Podiums which were the stars of the show and close behind was Herbies Audio Labs various products i found the Tenderfeet performed better with the Supersonic Stabilisers.
The Stillpoints were last but most expensive by miles i did not like the hard coloured sound they brought to my system second to last was Symposium Rollerblocks again costing multi thousands they also brought a hard colouration to the sound not as prominent as Stillpoints but still there. The Final Daruma 11 perform better the Symposium Rollerblocks at a third of the price.
Just my personal findings in my system cost of around 40,000 includes cables.