TY - MANSCPT DB - Science History Institute DP - Science History Institute M2 - Courtesy of Science History Institute. Rights: In Copyright - Rights-holder(s) Unlocatable or Unidentifiable TI - Beckman Model AB-4-6 Semi-Automatic D.C. Resistance Tester ID - 5712m664x AU - Commercial Photographic Company DA - 1950/// YR - 1950 AV - Beckman Historical Collection, Box 79 VL - Beckman Historical Collection, Box 79 AN - Beckman Historical Collection, Box 79 UR - https://digital.sciencehistory.org/works/5712m664x KW - Scientific apparatus and instruments KW - Beckman Instruments, Inc. LA - ER -