The IOD system is a name of a mechanical device for Gears that exclusively appears in Crush Gear Nitro. It has the ability of rotating a Crush Gear by using the protuding arm shaft from the Gear's side. IOD stands for Intermittent Operating Device.
The IOD system is usually attached to the rear of a Crush Gear. A Gear equipped with the device has the ability to rotate by triggering the arm shaft located at the side of the Gear.
Timing is vital to ensure that the Gear triggers the device at the right moment in battle.
There are two types of IOD units that are used throughout the series, namely:
- Single-unit IOD, in which the rotating arm is located on either side of a Crush Gear. The direction of the Gear's rotation depends on which side the rotating arm is placed. Left unit IODs rotate to the left when triggered, while the right unit ones rotate to the right.
- Double unit IOD, in which the device is equipped with two arm shafts. This unit type gives a Gear a boost of power when both of the rotating arms are triggered subsequently.
The IOD system was first developed by Ginjirou Fujiwara for his brother, Kinichiro to use on his Gear. During a Gear Fighting competition, the power of the device was deemed too overwhelming for Kinichiro to handle and it was worsened with his Nitro. On the night where the Fujiwara brothers' place was burnt down, he desperately wanted to take the device although Ginjirou tried to stop him. Kinichiro scarred his own palm when attempting to take the IOD system since it became hot during the fire.
Some time later, the IOD system is developed by the Sanama Laboratory. In the earlier episodes of Crush Gear Nitro, King Schwarz, Wingraptor and Iron Wolf are the Gears that are equipped with the device. The IOD system is eventually marketed to the public and most Gears have the device attached.