Do you mean these?

universal round plant holder

I've seen them without the bottom - just the ring around the pot itself, but those were DIY holders.

Came across these that look interesting: pot rockit

HTH ....

PV

thanks. wow, their rock it and lock it plant holders look amazing. i've emailed them to ask if they can clarify their return policy, as it says anything returned must be 'unopened', which makes no sense to me. How can you know if the items works for you if you can't open it??