50/50 rail

Surfboard rail design where the deck-to-edge curve, in cutaway, is more or less symmetrical with the bottom-to-edge curve. As compared to the dropped-profile "hard edge" rail, the 50/50 is forgiving and easy turning, but tends to allow a board to fall out of its forward-moving track into a spin-out. The 50/50 rail—also known as an egg rail—for the most part is used on longboards or funboards, and works best in smaller waves. Also known as a "soft" rail.