• Country
• United States of America (USA)

• Manufacturer / Brand
• Industrial Instrument Service Corporation; Chicago

• Year
• 1951 ??

• Category
• Service- or Lab Equipment

• Radiomuseum.org ID
• 97711

• Wave bands
• - without

• Power type and voltage
• Dry Batteries / 4 × 1.5 Volt

• Loudspeaker
• - - No sound reproduction output.

• Material
• Metal case

• from Radiomuseum.org
• Model: 421-D AC-DC VOM - Industrial Instrument Service

• Shape
• Very small Portable or Pocket-Set (Handheld) < 8 inch.

• Dimensions (WHD)
• 3.25 x 6.2 x 3.25 inch / 83 x 157 x 83 mm

• Notes
• Copper-oxide rectifier for AC.

• Price in first year of sale
• 20.00 $

• Literature/Schematics (1)
• 1951 Newark catalog Nº 51

• Author
• Model page created by Vitor Oliveira. See "Data change" for further contributors.

• Other Models

• Here you find 8 models, 8 with images and 0 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Industrial Instrument Service Corporation; Chicago