"Lobster" wrote in message
om...
"TheScullster" wrote in message
...

Yes I would have googled first, but don't know a suitable key word

I know www.ironmongerydirect.com do them; fairly expensive though.
They are intended for fire safety purposes - they are intumescent,
which means that in the event of a fire they expand (bit like that 'no
more gaps' foam stuff) to fill the hole made by the downlighter to
inhibit the progress of the fire.

David

Ah, didn't think of that ... I don't think my earthenware flower pots do
that! Ho hum.