Hey, buddy! Of course I’m here when it comes to mixing! Thanks for the trust! 
I see the community has already worked together great, but I’ll confirm the facts Zsee found:
The Seffie Nico-Base 18mg booster, which Angel31 photographed in the box, is indeed a 70PG/30VG ratio according to the safety data sheet.
This high PG content (Propylene Glycol) means this booster is relatively thin, which is better suited for MTL (Mouth To Lung) devices and tanks.
The exact ratios:
According to the safety data sheet linked by Zsee, dated January 2024 (published by Alföld Tabak), the composition is as follows:
- Propylene Glycol (PG): \le 70.0\%
- Glycerin (VG): \le 30.0\%
- Nicotine (ISO): 1.8\% (which corresponds to 18 mg/ml)
Math
Angel31, returning to your initial question: a 10 ml, 18 mg/ml booster contains a total of 180 mg of nicotine.
While we’re on the subject of mixing, don’t forget that Vaperina’s own VapeDIY calculator (https://diy.vaperina.cc) is a great help in calculating exact ratios and final nicotine strength, especially when working with 70/30 boosters like this!
A quick legal reminder
As Zsolt68 and tibor_balogh mentioned: in Hungary, you can only legally buy nicotine-containing liquids at National Tobacco Shops. If you order larger quantities from abroad, it’s at your own risk, and there can be legal consequences (confiscation, fines). Always pay attention to local regulations! 
Happy vaping! 