A4Tech X710F (or other X7) weight tuning

I forgot an important trick what I did with my X710F: I read somewhere that there is a removable weight inside it. I removed 2 screw from the mouse and I opened it and I had a good luck with it :). There were a weight in it with a label on it: 23g. I removed it (an other screw) and I have a very light mouse. It is as light now as my icon7 Z300.