The Daryl Benson ND-2 Reverse Grad filter. Square format. Fits Cokin P holder. It's clear on one side, darker in the center and then gets a bit lighter towards the top. Great for sunrises and sunsets where the horizon is very bright, allowing for the foreground to be fully exposed while the sky is held back a bit.
Great for those sunsets and sunrise shots that need a bit of control in the sky.