What tube grades are available in the MH-1?

“Adams Industries configures the MH-1 with Gen 3 tubes from Elbit Systems of America across multiple FOM tiers (1600–2000, 2001–2376, 2377–2600, 2601+) and from L3 Harris Technologies (standard filmless, high-performance filmless, and the Supergain). Tube pairs are hand-selected and matched for balanced image quality between eyes — mismatched pairs are a documented source of eye fatigue in binocular systems.”