Simple Circuit Modules. These modules may be used to construct simple circuits of the type normally implemented on, for example, a Worcester Circuit Board. They are intended to introduce younger pupils (ages 11-13) to some of the more familiar applications of devices and circuits, the main emphasis being on simple electrical circuit work. The modules are 60 x 60mm and have 4mm plug connections. The ISMEC Kit comprises:. 10 x 4mm Stackable Plug Lead 250mm - Red. 10 x 4mm Stackable Plug Lead 250mm - Black. 1 x Ismec 11-13 Push Button Switch 4mm. 5 x Ismec 11-13 Led Red 4mm. 1 x Ismec 11-13 Motor 4mm. 1 x Ismec 11-13 Buzzer 4mm. 5 x Ismec 11-13 Led Green 4mm. Stored in a shallow blue Gratnells tray with lid.