Thanks for your kind email. I need the following items, please: Erbium Fluoride. The size of particles should be less than 90 micrometers and particles smaller than 50 micrometers should not be more than 50% of the sample weight. The shape of particles should be spherical. The required amount is 40 kgs in the first phase. Tantalum Oxide The size of particles should be less than 90 micrometers and particles smaller than 50 micrometers should not be more than 50% of the sample weight. The shape of particles should be spherical. The required amount is 40 kgs in the first phase. And about the procedure of buying, the suppliers should first send 100gr sample for us, and after the end user approval, we will buy it. Looking forward to hearing from you. Best Regards Sama s.hadadi83@gmail.com