Most microphones are optimized to record sound comming from a single direction. Obviously, sound comming from other directions are recorded as well, but their volume decreases, the farther they are away from the sweet spot.
Mic screens are therefore prettymuch useslees for directed microphones, since thes dampen the sound comming from behind the microphone, which is the direction it records with the least volume. What would help is making this screen larger and install it behind your head to dampen the reflections that hit the microphones sweet spot.
Now if your recording setup is e.g. fully encased in glass, then yes, this Micscreen might improve your sound, since it would slightly reduce the amount of reflections created by your singing. But so would 10 bucks worth of cloth hanging over the glass to prevent high frequency reflections from all sides.
If you want better sounding vocals, spend some money to accustcally treat your recording space. And if money is an issue, start with the area directly behind you (e.g. fit a corner of your room alternaingly with absorbers and diffusors and record with your back facing the corner at a short distance).
If you already have a accustically decent recording space, this micscreen will do nothin for you.
Yes there are microphones that are optimized for multiple directions, but if you want to dampen all direcions except for one, you are using the wrong microphone.
