Re: Tub strainer w/pop-up plug?
Those pop-up plugs are screwed into the drain. Turn it counter-clockwise to remove. Once out, measure the diameter of the drain neck and pick up a strainer cup to fit. When you're looking for a strainer cup, I recommend the type without a center peg. While initially the peg looks like it would be helpful when removing the strainer for cleaning, we've found that it gets in the way, both for removal and for cleaning. I broke the peg out of our strainer and it's much easier to service now.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!