The M1 was a series of experimental Republic

Galactic Republic Organization Galaxy-Wide Organizations

war droids designed during the Cold War

The Cold War Event Cold War (3653BBY - 3642BBY)

.
The droids were designed to serve in the Havoc Squad

Havoc Squad (Republic Special Forces Division) Organization Galactic Republic (GGW, CW and GW)

, but the project was cancelled before completion - the droid's design relied on an exotic alien power source, but Republic technicians

Technician Miscellaneous Roles

were unable to make it work effectively.