I don't know exactly which particular so-called "squirrel-proof" one which would work best or which might be available ready-made.
I reckon that if I were trying to make one which really would work, I'd get a circular tray made from metal or really strong plastic - at least 30" diameter - and make a hole in the centre which would be large enough to push a metal spike-type bird-feeder post through it. You know the sort of thing - usually black & with a hook at right angles at the top from which you'd normally hand a peanut feeder or suchlike.
If you push the spike through the hole & fix it so's the tray can't move, then squirrels can't climb up & over it it to reach anything which is hanging above. I think I'd try to get the tallest pole I could find, and make sure that the tray was at least 4 ft from ground level. The tray would need to be upside down, so that any lip pointed downwards - that would make it even harder for a squirrel to climb over. A small tray wouldn't really be any good - they can reach quite a long way!