How big will he get?

[zina10]

I have adopted my male when he was 3 years old and he was 3 feet. What surprises me is that it’s written on his identification paper which was issued when he was born that he would reach a maximum length of 4 feet. And it’s true. He is now 5 years old and 3,6 feet. How did the breeder at the time of his birth know that he would reach only a maximum length of 4 feet? By the way, I’m happy with his size, it fits his new enclosure very good. I’m just not happy with his feeding habits

I would say the breeder put "general" information on the papers. Males "usually" reach a maximum of 4 feet long.
Anything between 800 and 1600 gr is considered normal for a male. There are exceptions, as with everything.