* Futures surfboard fins * Material: Fibreglass * Size: Large * Neutral template * Futures brand details * Colour: Black Marble The Son of Cobra Twin has an extra cant angle that will fit any Post-modern Twin fins. This includes the new ...Lost Cobra Killer, and other Son of Cobra Round Twins. These fins are designed to be used with the Lost Surfboards x SOC \"Cobra Killer\", a model that has a 7.5-degree cant angle (standard for twins). The solid fiberglass construction with balanced height and base measurements gives maximum drive. The thinner tip allows for release and spring off of the top.