Flip-ItŪ Tub Stopper: The Amazing Fit-All Replacement Tub Stopper
Their words, not mine, Terry
It may be amazing though. Or at least it's a fix for a problem that's becoming more common.
Useful when the linkage on a tub drain no longer works. Will fit 90% of tub drain openings. Slip on an O-Ring and press into the drain.
A ball-shift toggle system which opens and closes the drain.