These are homemade power adapter for the TRS-80 Model PC-2 ( aka Sharp PC-1500 ) line of calculators/computers.

This will allow you to power your Sharp PC1500 / Tandy PC2 a standard USB power pack.

This is a step up converter to the proper DC voltage the Tandy/Sharp expects; on the proper diameter barrel jack that is a tight fit.  

You only get the black USB power cable (around 80cm long), not the battery packs, the computers, or the multimeter that you see on the pictures. :-) 

These are built by a fellow Tandy afficionado, and all tested before shipping on my own PC-2.
You can use your computer either without AA batteries at all, or with batteries in it - in which case the unit is powered by USB as long as it is connected, and AA cells are used when you unplug.
Also be sure to clean and deoxidize your female barrel connector (Kontakt60, DeOxit, etc) for maximum reliability.

International Shipping with Belgian post :