ADAFRUIT INDUSTRIES 85 SHIELD STACKING HEADERS ARDUINO (R3 COMPATIBLE) (1 piece) Our set includes 1x 10-pin header, 2x 8-pin headers, 2x 6-pin headers, and one 2x3 header. The legs are all 10.5mm long, so after PCB thickness (1.7mm) you have a height of 8.8mm - just enough to clear the Arduino's USB-B connector Theyre also fully compatible with shields designed for Arduino R3 and the Leonardo shields that dont use the 10-pin header or 2x3 header, use the 6 or 8 pin ones.