I fish for small lakers. Quite often they bite very lightly. A buddy who uses slip floats got me started using them. I use a modified version of the clip-on yellow foam ones. He uses those with holes in the middle. Quite often the float bobs around for a few seconds, then gets taken under. Then it's time to set the hook. I don't fish for panfish but I would imagine they would be quite effective sometimes with perch, crappie etc.