1. Grade :5n,6n 2. 5n purity :99.99926% . 6n purity :99.99994%. 3. Physical purification method. We have inspection certificate/certificate of inspection. And insure the quality of the products !. 1. Grade :5n,6n. 2.  5n  purity :99.99926%  .    6n purity :99.99994%. 3. I sell that for my friends. 4. Product quality is steady.