Tektronix DTG 5274 Data Timing Generator (2.7Gb/s; s/n J300159), as shown. It is in good working condition, and comes with a Calibration Certificate (Calibration Date: Aug 15, 2008; In Service Date: Feb 17, 2009, Calibration Due Date: Feb 17, 2010). It comes with many accessories, as shown. Please see the last photo below for a complete list of accessories included.