The Tektronix 201 is an oscilloscope cart designed for the 422, 503, 504 515, 516, 561, 564, and 647. The width of the tray is 10.5".
There is a 201-1 and a 201-2. The 201-2 has a carrier for plug-ins. The 201-1 does not have this.
201-1 Model D
Tilt-lock feature on 200-series carts