A-107 soviet Vintage Dekatron Nixie Tube New 1MHz

The shaped cathodes limit the tube to unidirectional counting, but maximum counting speeds are quite respectable; the neon-helium filled A-108 can count at up to 10kHz and the mixed gas A-109 will count at up to 100kHz, whereas the high speed A107 can count at a blistering 1MHz.