Wikipedia
The dicker-rod (also spelled dickerod) was used in the defunct World Football League in 1974 for the purpose of replacing the first down chains more commonly used in gridiron football organizations. The device was invented and patented by George Dicker of Orange County, California.
The device was two and a half yards (90 inches) long. If a ball was placed on the 23-yard line, a marker would be placed 2 yards up the rod at the 25-yard line. Then, in order to measure whether a first down was attained, the dicker rod would be laid down at the 35-yard line, and the spot of the ball would be measured against the marker on the rod, which would now be at the 33-yard line, 2 yards away from the 35-yard line.
The dicker-rod was intended for convenience. A full chain crew was not needed, and measurements could be conducted by one person instead of the typical three. However, it never caught on, and the three-man chain crew remains the standard.