Review of the GigaWave 9400 6GHz, 4-channel sampling oscilloscope
EEVBLOG, discussions about the GigaWave 6400:
https://www.eevblog.com/forum/testgear/pocket-sized-6-ghz-1-tss-et-scope/msg5261496/#msg5261496
SJL Instruments
https://www.sjl-instruments.com/