On Christmas Eve I finished building this simple piece of test equipment from QRPkits. It's a combined signal tracer and injector. It doesn't do anything that I cannot accomplish with an oscilloscope and a function generator but it's much more convenient to use.
As with the Accuprobe described in my previous post, this device uses heat-shrink tubing as a case. At Joanna's suggestion, instead of using a hair dryer as a heat source, I simply place the unit on top of a space heater (as shown in photo) with the air flow directed vertically. This worked much more quickly and provided more uniform heating.