When I ordered the filter on September 15, 2021, I chose economy shipping with a delivery time of 4-10 Business Days. That meant the filter would get to me no later than September 29, 2021. Since my Waterdrop RO system had just gone into the "yellow" phase on the 14th of September, I felt I could wait that long to receive it, so I chose the economy shipping option. Now I am being told that it will not arrive until October 5, 2021, at the earliest. If I had know the true delivery estimate, I would have chosen a different shipping option or bought a replacement filter from a different vendor. As inferred above, I still do not have the filter. Very disappointed!