Flexible Prototyping Boards Twin Industries Flexible Prototyping Boards incorporate the latest flexible printed circuit board materials. These prototyping boards come with 32-plated holes per side that are connected by dedicated traces to 32 holes on the opposing side. The flexible prototyping boards employ SMT pads for capacitors, resistors, or other components. These prototyping boards feature polyimide material with FR4 stiffeners. The flexible prototyping boards are available in both circle (5001F) and square (5002F) shapes. Twin Industries Flexible Prototyping Boards are ideal for flex PCB development, wearable product development, and flexible printed circuit board assembly process testing.