The underground metal structure in the radiation field of the radio frequency antenna can be equivalent to the receiving antenna. The energy of electromagnetic wave focused on the metal structure will be released in the form of discharge spark under scratch condition. At present. there is no testing method and experimental equipment to measure the discharge spark caused by electromagn... https://www.bekindtopets.com/discount-Ancient-Roman-Gladiator-Murmillo-Cassis-Crista-Helmet-With-Medieval-Style-Skullcap-Nasal-Helmets-With-Nose-Guard-3-Re-big-savings/