Looks identical to the pocket dolly. Any idea if there are cheaper alternatives for support for the slider? I'm looking for feet for my pocket dolly but can't find anything cheaper that's comparable to these:
I can't see the picture clearly, but it does not look like they use true ball bearings. They look like low friction plastic sliders, such as those used by Igus. If this is true, it will work ok at lighter loads. At heavy loads, the friction will increase and it will catch. Also, plastic bearings needs to be perfectly aligned or they will catch. Ball bearing can be noisy if the wheels are not designed correctly or if the rig is moved very quickly. For a slider, ball bearing is the way to go, but quite a bit more expensive.