A flat drain cover catches hair on top of itself, in plain view, where you have to look at it and then pick it up. That is the one that ends up in the cabinet under the sink.

This one sits down inside the drain instead. Water goes through the middle, and the hair wraps around the outside of it below the surface, out of sight. When it needs doing you lift it out, wipe it in one motion, and drop it back.

What you do now is nothing, until the water stops going down. Then you either fish around in the drain with your fingers, or you buy a bottle of drain cleaner. You buy that for the hair already in the pipe. It does nothing about the hair going in tomorrow, which is why you buy it again.

The hair does not get past it into the pipe, which is the actual point. The clog you are preventing costs more to clear than every drain tool you will ever buy put together.

Out of sight is also where this one goes wrong. A cover you can see nags you. This one does not, so it is easy to leave until the drain has already slowed. Pick a day of the week and lift it on that day. Wipe it into the bin rather than under the tap, or the hair goes straight back down a drain. And if you live alone and nothing in your house sheds, a flat strainer is still fine.

Check your drain diameter before ordering. It has to seat properly to work, and the wrong size either will not sit down at all or lets water back up around the edge, and both of those turn a good product into a returned one. Measure the hole itself, not the trim ring sitting around it. If your tub has a stopper built into the drain that you cannot lift out, work out where this would go first. A 4.7 across 33,505 ratings says it works in a lot of houses. It says nothing about whether it fits yours.