Nixie Tubes Clock IN-18 on PCBs for 4 Tubes(without tubes). 1 pc of MCU board: NCM109 (If You want build your own CUSTOM nixie tubes clock, You may buy only MCU PCB). Clock support many kinds of Nixie tubes (4 tubes [hh:mm], 6 tubes [hh:mm:ss] and 8 tubes [HH:MM:SS:uu /Temp]).