The Go / NoGo tools are two pieces of cardboard, of different thicknesses, that verify the success of the calibration. The Go tool passes through the space between a pair of correctly calibrated tool flanges. The NoGo tool cannot pass between that space.

After calibration, when the Calibration Connector is removed and the tool flanges approach each other, use the Go / NoGo tools to verify the distance between the tool flanges.