The electric field strength (in volts per meter) at which breakdown occurs is an intrinsic property of the insulating material called its "dielectric strength". The electric field is usually caused by a voltage difference applied across the material. The applied voltage required to cause breakdown in a given insulating object is called the object's "breakdown voltage". The electric field created in a given insulating object by an applied voltage varies depending on the size and shape of the object and the location on the object where the voltage is applied, so in addition to the material's dielectric strength, the breakdown voltage depends on these factors.