The The equipment identification informs, amongst others, about the ambient and environmental conditions in which the device may be used. informs, amongst others, about the ambient and environmental conditions in which the device may be used. This information also includes the Within a group of units, the category defines the classification with regard to the required level of safety. The device category indicates the technical requirements placed on a device for the individual Ex zone., the device group, the The maximum temperature or surface of a device, a protection system or a component can achieve during operation under the most unfavorable conditions., the Special measures taken on devices to prevent the ignition of the surrounding atmosphere. and the notified body having inspected the device concerned.