They are made for bonsai. They are bonsai turntables. Hard graphite with stainless ball bearings. No rusting!!!! I got them from ebay. About $10 each and they hold up 200lbs I think. Many bonsai tree's are heavy. Mine are. Turn the tree without lifting. I can examine all sides daily with no prob.
I can't use cheap dollar store ones for heavy bonsai. I also use them for work turntables. When I am styling a tree I probably turn it 50 times or more for perspective. do something and then turn the tree and see what it looks like from all sides. The only thing better is if they were motorized so I could view from a distance. I guess I need to look for an old record player
I love them and will probably be ordering more.
Tom