Which of the following is a key characteristic of an EED?

A key characteristic of an Electric Detonator (EED) is that it initiates explosives through the application of electric energy. This characteristic is central to the function of an EED, as it relies on an electric current to trigger an explosive reaction. The ability to use electrical energy for initiation allows for precise control over timing and placement, making EEDs essential in various applications, including construction and military operations.

While some EEDs may be portable and compact, this is not universally true for all EEDs. The assertion that they are primarily used for training purposes is also misleading, as EEDs are widely employed in real-world explosive applications beyond merely training. The claim that EEDs do not contain any explosive materials is incorrect, as the device itself generally contains a small charge that, when activated, initiates a larger explosive.

Thus, the defining aspect that sets EEDs apart is their reliance on electric energy for explosives initiation, which is accurately captured in the correct answer.