Littlebits hardware development kit the hardware development kit hdk is the quickest way to get started developing your own module for the bitlab the two proto modules allow you to connect to pcbs and breadboards while the perf module allows you to build a small circuit right on the module when youre ready to design your own pcb you can use the included gray bitsnaptrade connectors to attach to the board weve also included color coded stickers so you can easily denote your bitsn