These are a recycled polystyrene foam blanks (no stringers) that have been made from your old foam packaging rather than it going to landfill it is granulated and steamed into a block and the blanks are hotwire cut from the block. There is the standard rockers for short board, fishes , mini mals and longboards. There is also the ability to custom cut a rocker/ blank to your specs. We can even supply SUP blanks. You could add a 1 inch balsa stringer for $100 or even a 4mm cedar for $80.