This is a swallowtail. Its straight rails come out to the tip, just like your square tail, but then it's got a big V from point to point. What that cutout does, it gives you a lot more control compared to the square tail, if it was straight across. Now you've got the V giving you control, and also in these boards, a lot of times they'll run V off the tail of the board to help the board come over rail to rail. Swallowtails go rail to rail. As you're transitioning from rail to rail, the swallowtails do the transition very easily. With a straight line at the very end of the tail, it helps with the projection and the holding of the board. Your swallowtails are common on fish boards, which are your wider summer boards, and also swallowtails can be brought in really narrow on your guns. They like the straightness of the rail line for projection in bigger surf. Your swallowtails can also be even wider than this on your fishes for more area and for smaller surf and better planing. You have a lot of planing surface in the swallowtail, which is fun for those small, mushy days. And that is the swallowtail.