Rust inside, it's an iron ring.
Praise is false, I actually give the poor. Customer service recommendation is wrong, harm me to buy a small, can only buy large. Other stores, 20 is 62mm, the store's number 18 is 62mm, said the size is not the same. I can only trust customer service. And
It was just junk slot
![](http://img.alicdn.com/imgextra/i1/155560330047685661/TB2u7p5em1I.eBjy0FjXXabfXXa_!!0-rate.jpg)
All rusted!!! Not buy!
I love it