Basically they are an enhancement kit board game (Sometimes called a Dog Bone, due to the shape), which plugged in to the mainboard of Electrocoin MK2 type boards (They don't work on MK 1's, same as the Concept / MAB one's), which gives the operator, several different games, based on the original electrocoin games (Due to legalities and to avoid confusion, they are NOT the same code as what Electrocoin use), like Bar-x, Big 7's, Red Bar etc.
