40 Pin GPIO Extension Cable for any 2x20 Pin Raspberry Pi [150mm / 6 long] : ID 4823 : $2.95 : Adafruit Industries, Unique & fun DIY electronics and kits
40 pin GPIO Reference Board For Raspberry Pi B+/Respberry Pi 2 - CodeScript
Raspberry Pi 40 Pin GPIO Reference Board – Geekworm
Adeept Raspberry Pi GPIO Breakout, T-Board + 830 Point Breadboard + 65 Jumper + 40 Pin Cable – Oz Robotics