MBC Battery holder, double

Used to make experiments in Electrics, serial or parallel connection of voltage sources e. g.;
magnetic block "compact" (MBC) with two mounted battery holders,
sturdy plastic housing (ABS) with transparent base, printed circuit symbol (screen-printed),
jacks also suitable for 4 mm safety plugs, base with embedded neodymium magnets,
supplied without batteries
dimensions: approx. 84 x 84 x 39 mm