Piggy banks are usually made of ceramic or porcelain. They are generally painted and serve as a pedagogical device to teach the rudiments of thrift and savings to children; money can be easily inserted. Many piggy banks have a rubber plug located on the underside; others are made of vinyl and have a removable nose for easy coin access. Some incorporate electronic systems which calculate the amount of money deposited. Some piggy banks do not have an opening besides the slot for inserting coins, which will lead to smashing the piggy bank with a hammer or by other means, to obtain the money within.