Traffic Control Marker Signs
Marker signs, including M1, M2, M3, M4, M5, M6 and M7 series,
cover route markers, junction signs, cardinal direction auxiliaries,
alternative route signs, advance turn auxiliaries, directional
arrow auxiliaries, and directional arrow auxiliaries (Bicycle).
Below are most of the signs with dimensions and part numbers.
Mouse over one and you will see a larger version of the sign.