How to know if the ball is good

Hello I play table tennis since the past year and in Egypt the shops aren't that good so I need to know how to say that this is a good ball or this is a knockoff thank you for your site

Hi Arsany,

Firstly check the hardness of the ball.  Press around it and see if it is really soft. It needs to be able to resist some pressure of your fingers.

Then you can also check if it is round.  Spin it with your fingers on a table like a Top and see if it is round.

We have an old video on this. Choosing a Ball.

Also check the branding.  Usually a 3 Star ball is better quality.