The Ausbausystem für Buchlabor cassette edition was the second version of the expansion model for the Buchlabor model. This edition was first released by LectronMW (Lectron, GmbH).

The first version had been sold by the INELCO Company as a red shiny vinyl 3 folded panel book (the Red Book).  The Red Book was also sold by LectronMW (as evidenced by the green sticker) until the inventory of those units was exhausted.  Unfortunately, the actual manufacturer of the INELCO models is unknown (as of October, 2019).

The Ausbausystem für Buchlabor model included the both standard 90 experiment manual (even though many of its experiments could not be done even with the Buchlabor and this model put together) and the the Elektrik I A 4 format Lehr-und Lernkartei (teaching and learning cards) documentation from the System 1100.

32 experiments were presented in the Lehr- und Lernkartei. One black ink page showed the experiment schematic with an overview and a series of questions. The second page, in blue ink, provided the answers with more detail and expansion. New information was also be provided in context with the experiment. For example, frequency modulation was introduced and discussed in the answer page while not actually demonstrated by the experiment.

An eBay acquisition in April of 2014 shows that an early release LectronMW cardboard box version used a Braun cover without any model verbiage on the front with a simple blue label on the side delineating the model type.

Note the LectronMW logo on the right of the graphic.

When the Braun boxes were used up, then the standard LectronMW box was used which featured the same green label to delineate the model as the Red Book had used.

The graphic below shows a later LectronMW era production unit of the Ausbausystem für Buchlabor complete with cover (covers were, with very rare exception, not shown in the brochures). Note the green sticker which is the same one that appeared on the Red Book which was used to cover up the INELCO branding.

Note that in this particular unit, the A5 format Lehr-und Lernkartei, which were provided in the Red Book, were also included here rather than the A4 format curriculum which the brochure graphic showed (first graphic at the top of this page).