Additional Features:

Up to three single width modules can be plugged into the Tektronix TM503B, or one single and one double width module can be accommodated.The Tektronix TM503B, Power Module, is compatible with all TM500-Series plug-ins. 
The Tek TM500-Series of plug-ins includes oscilloscopes, function generators, scope calibration equipment, DMM's, counters and power supplies. Also choose from pulse generators, operational amplifiers, bandpass filters, and current probe amplifiers. You may be able to fit every instrument you'll need into one small mainframe.