These 2100 x 100mm feather edge boards are mostly used by our customers to build closeboard fencing and will be attached vertically to fence rails (known as Arris rails).
The term feather edge refers to the shape of the board. Each one starts out as a single 22mm thick board which is why we list them as EX 22mm. This is then machine cut diagonally to make two feather edge boards - each with a taper from thick (approx. 15mm) to thin (approx. 6mm).