The contents are roughly of 3 types: active modules, sensors, and accessories…. And a couple of nice surprises.
 
The BT module with its SLC pins .

Let’s start with the 12 modules which are in the form of rectangular tablets of 4x3 cm, easily stackable like Lego® bricks, with which they are mechanically compatible . This will be a strong plus for anyone seeking equipment with educational value. Each tablet is made of a printed circuit board of 3 x 2.5 cm with two sides having a plastic holder which is compatible with the famous Lego® bricks. They’re small, but not too small.

The electrical coupling between modules is cleverly done with three lines of pins (27 in all) arranged in a U on three sides of the boards. No, these male pins of POGO or SLC (Spring Loaded Connector) don’t fit into female sockets on the other card as we are used to, but press against the flat gold plated surface at the top of the pins of the neighbouring card below.

 
Detail of the POGOs or SLC connectors.

And it’s here that we find the 3rd truly remarkable characteristic of the mCookies modules: the modules are held together by magnets, 4 altogether, they are embedded in the plastic edges of the cards, one at each corner. Instant assembly and disassembly, and perfect electrical connection!.

All this is extremely well designed, and the quality of manufacture and the finish is close to perfection. The cherry on the top is the magnetic polarity of the magnets. The modules are not mechanically interlocked and can be connected in any order, but the polarity of the powerful magnets prevents you from connecting a module upside down and pushing on it. You have to push hard and try several times to intentionally overcome the repulsive force of the four magnets. This tactile experience, difficult to describe in writing, is a strong learning component for students.