As you can see from the last photo there is no a size stamp, but when I put it on my head I feel it as 57 (to 58). That is why I just wrote "size M". In real there are not any big wholesalers in Bulgaria.
Here is:Bulgarian Army Combat STEEL Headgear M51. In real there are not any big wholesalers in Bulgaria. So, I do advise you to get the item you like right now. I do all of this because I know, that you are looking forward to receive your item.