What does CHINA use? Several years ago I bought an outdoor light made there. it included two lag bolts to screw it in place.
Problems;
It was between my two metric sized sockets (10 and 11). My “Inch” tools would not fit.
So out came the adjustable Crescent wrench. It was a tough area to get to but none of my sockets would fit it.
Did you use an English or metric crescent wrench?
China still uses the Wentworth system that the British gave them 100 years ago.