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>>These have the 1/2 x 1/2 wire so that feet can't get stuck in them.

I thought about this after I posted it & thought that's not right.
I measured the wire on those wheels & it's actually 1/4 x 1/4 spacing.
Most rodent product catalogs carry them I think you could find one on a website to look at if you googled one.
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PHRatz