18 U.S.C. 2510, et seq., constitutes a statutory system of regulating interception of wire, oral, or electronic communications. Any person contemplating the mailing of a device primarily useful for surreptitiously effecting such interception should consider the provisions of 18 U.S.C. 2510, et seq., particularly section 2512. This statute makes it a crime, except as otherwise provided in 18 U.S.C. 2510, et seq., for a person intentionally to send through the mail any device whose design that person knows, or has reason to know, renders the device primarily useful for surreptitious interception of wire, oral, or electronic communications. The statute does not declare that such a device in itself constitutes nonmailable matter but, as indicated, provides criminal penalties for the act of intentionally mailing it.