Date of intro: ~1966,
Power: AC,
Display: Type = Display (Nixie) (List), Digits = 12,
Number of keys: 28, #Key-Black: 1, #Key-Green: 4, #Key-Grey: 11, #Key-Red: 1, #Key-White: 11,
Keyboard Array (Rows x Columns): 05x07,
Classification: / Desktop with Display,
Featuring: Square root,
Serie-members: SUMLOCK ANITA ELECTRONICS: Anita MK12 (version-1) (26 keys); SUMLOCK ANITA ELECTRONICS: Anita MK12 (version-2) (27 keys, metal keyboard); SUMLOCK ANITA ELECTRONICS: Anita MK12 (version-3) (27 keys, plastic keyboard); SUMLOCK ANITA ELECTRONICS: Anita MK12 (version-4) (28 keys, with Sqrt),
Known Serial-numbers: MK1272633K2 (MK 12/72633/K/2) (List of all S/Ns from SUMLOCK ANITA ELECTRONICS)
Courtesy of: TIMMERMAN Gerard,
Info: Info from TIMMERMAN Gerard:
This is a rather strange version, which is supporting a Square-Root Key.
Perhaps this version is made in a small production run, or someone achieved some customizing, the Square-Root key does not match the design of the other keys.

!!! This item is WANTED to join the collection !!!