The Act provides a number of specific exemptions from the general requirements described in Sec. 780.1. Some are exemptions from the overtime provisions only. Others are from the child labor provisions only. Several are exemptions from both the minimum wage and the overtime requirements of the Act. Finally, there are some exemptions from all three--minimum wage, overtime pay, and child labor requirements. An employer who claims an exemption under the Act has the burden of showing that it applies (Walling v. General Industries Co., 330 U.S. 545; Mitchell v. Kentucky Finance Co., 359 U.S. 290). Conditions specified in the language of the Act are ``explicit prerequisites to exemption'' (Arnold v. Kanowsky, 361 U.S. 388). ``The details with which the exemptions in this Act have been made preclude their enlargement by implication'' and ``no matter how broad the exemption, it is meant to apply only to'' the specified activities (Addison v. Holly Hill, 322 U.S. 607; Maneja v. Waialua, 349 U.S. 254). Exemptions provided in the Act ``are to be narrowly construed against the employer seeking to assert them'' and their application limited to those who come ``plainly and unmistakably within their terms and spirit'' (Phillips v. Walling, 334 U.S. 490; Mitchell v. Kentucky Finance Co., 359 U.S. 290; Arnold v. Kanowsky, 361 U.S. 388).