This is matched quartet of Raytheon RK 75 (307A, VT225). This
is very rare version of 307A, with just three ribs, all other versions have 5
ribs. This tube is also characteristic for double symmetrical getters.

Click to see All 307A VT-225 306A in stock


This Post Has One Comment

  1. Cody Box

    how much were these worth? I have 5 matching tubes in original packaging. 3 ribs. dated Aug 31 1944

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