8-bit Workbench™ + Super Breadboard 2 + Binary Keyboard DIY Kits by 8BitFlux

One part is tiny and needs a smaller than usual soldering tip (see the pictures with all the parts). A neat 8-bit toggle keyboard (one byte) to extend the 8-bit Workbench™: use the action-button to deposit the toggled byte and see its hexadecimal or octal representation right away.

eBay