Raspberry Pi Traffic Light and GPIO reference board combo pack for the Raspberry Pi A+, B+, Zero, 2, 3, 3B+ Raspberry Pi GPIO Plus reference pinout board only 0.8mm thick Pi Traffic Light for Raspberry Pi Both are compatible with Raspberry Pi Model A+, B+, 2 and 3 Reference pinout is idiot proof, really! You cant put it on backwards Traffic Light mounts vertically to the Raspberry Pi GPIO header and only uses four pins