What is the difference between K9 Crystal with K5 Crystal?
Crystal can be divided into K9 Crystal & K5 Crystal, K9 is better and K5 will be with bubble and air flow inside
For items in our company, we use K9 Crystal, however there are many grades among K9, like Grade A, Grade AA,
Grade AAA, Grade AAAA, Grade A is the best, however it is not so easy to recognize from the photos, which is
obvious to know on price.