Excerpt from Part 15

15.204 d) Except as described in this paragraph, an external radio-frequency power amplifier or amplifier kit shall be marketed only with the system configuration with which it was approved and not as a separate product.

(1) An external radio-frequency power amplifier may be marketed for individual sale provided it is intended for use in conjunction with a transmitter that operates in the 902–928 MHz, 2400–2483.5 MHz, and 5725–5850 MHz bands pursuant to § 15.247 of this part or a transmitter that operates in the 5.725–5.825 GHz band pursuant to §15.407 of this part. The amplifier must be of a design such that it can only be connected as part of a system in which it has been previously authorized. (The use of a nonstandard connector or a form of electronic system identification is acceptable.) The output power of such an amplifier must not exceed the maximum permitted output power of its associated transmitter.

(2) The outside packaging and user manual for external radio-frequency power amplifiers sold in accordance with paragraph (d)(1) must include notification that the amplifier can be used only in a system for which it has obtained authorization. Such a notice must identify the authorized system by FCC Identifier.