Up for sale is a Soviet tanker helmet that's got a stamp indicating it was manufactured in 1990. It's a bit dirty and faded due to how old it is. It's the winter variant that's been lined with fur on the inside. As for the size, it's definitely a medium as indicated by the stamp; specific measurements being 56-58 cm or 7" to 7" 1/4.
If you purchase this and it doesn't fit your head either, just let me know and I'll issue a refund.
Let me know if you think I got any of this wrong or if you want any more pictures.