Which of the following is NOT considered an incendiary device?

A garden hose is not considered an incendiary device because its primary function is to convey water, which is used to extinguish fires rather than ignite them. The materials and design of a garden hose do not support the production of flames or sufficient heat to initiate combustion. In contrast, a matchbook is designed to hold matches, which are tools specifically created to start fires. An electric heating appliance can generate significant heat, potentially leading to fires if misused or malfunctioning. A combination of a cigarette and matchbook also represents a fire risk, as both can synergistically lead to ignition. Therefore, the garden hose stands out as the option that does not serve the purpose of creating or facilitating the ignition of fire, making it the correct answer.