A SoundLab question

I have been wanting to purchase a pair of SoundLabs and am looking at a pair of A3. The question - They are equipped with 5 casters on each speaker. Is this common? It seems strange to me but I'm very new to SoundLabs.

Thanks for any input you can give me.
I have the A-3s and have removed the 5 casters and replaced them with 3 Walker cones. I placed the cones directly under the speakers, not using the metal holder for the casters at all. The improvement was much more natural sounding and the soundstage was wider and deeper. I then experimented with the Walker cone locations and can send you the measurements.
Casters are available as accessories, useful mostly for folks who either want to be able to adjust their speaker positions more easily or perhaps more likely want to be able to push the speakers off to the side when they're not being used. Sound Lab also offers cones (tiptoes) and carpet glides, the latter also usable on hardwood floors.

Much more important questions to ask are, when were the speakers built, and have they been serviced in any way, what do the backplates look like, and so on. There are other questions, but that's a start. Serial numbers can provide useful information.

Drop me a line if I can be of help. Good luck!