美国采购需求：7782-49-2，硒粉，硒，硒粉，纳米材料

I'm interested in your 99.99% pure Selenium powder, specifically looking for a -200 mesh particle size. Our initial order would be for 3 kg, and I'd appreciate it if you could provide me with your best pricing along with the estimated lead time for delivery. Additionally, I'd like to know if there are any bulk order discounts or special terms available for future purchases. Please include any relevant details about the product, such as packaging options and shipping costs. Looking forward to your prompt response so we can proceed accordingly!