Q: Can I get free samples? How long? A: Sure. We have stock, so we can offer the sample within a few days. Q: Payment options? A: T/Tor L/C. (OA & DP are not accepted) Q: Delivery time? A: 15 days since deposit. Q. OEM? A: Yes. Q. What proportions of NPK do you supply? A: We can offer all specialized NPK as long as the quantity meets our MOQ. Here is some NPK we have ever supplied: NPK15-15-15, NPK17-17-17, NPK19-19-19, NPK20-20-20, NPK12-12-17, NPK11-12-26, NPK12-24-12, NPK15-15-20, NPK11-22-16, NPK18-18-0, NPK12-22-11, NPK22-9-9, NPK26-11-8, NPK26-12-7, NPK16-8-22, NPK25-10-10, NPK25-14-6, NPK15-15-20, NPK12-17-16, NPK12-18-15, NPK28-14-6, NPK12-20-13, NPK24-11-10, NPK12-21-12, NPK24-10-8, NPK18-22-5, NPK23-13-9, NPK18-21-6, NPK16-6-18, NPK15-20-5, NPK12-26-10, NPK12-19-14, NPK18-5-21, NPK23-13-6, NPK25-15-8, NPK24-10-14, NPK27-12-11, NPK27-7-7, NPK13-17-15, NPK14-16-10, NPK15-8-22, NPK15-10-20, NPK20-14-6, NPK20-10-10, NPK16-6-20, NPK16-12-18, NPK16-8-20, NPK12-5-8, NPK22-9-11, etc.