The Keysight E2644A is a wedge probe adapter. If you've ever tried to probe a surface mount component, you've probably experienced one or more of the following frustrating situations: accidentally shorting IC pins together; electrical and/or mechanical problems with soldering small wires onto leads; and/or holding multiple probes and trying to use your scope at the same time. The Keysight Wedge Probe Adapter provides a solution to these frustrations.
It is easy to insert and stays put - no need to solder small wires onto leads. The Wedge is mechanically non-invasive, so you won't damage the legs of the IC. It makes two contact points with each leg of the IC. This redundant physical connection increases the electrical reliability of the connection.