Figure 4: The M2A capsule camera. The device consists of a disposable plastic capsule that weighs 3.7 grams and measures 11 mm in diameter by 26 mm in length. The contents include an optical dome (a), a lens holder (b), a short focal-length lens (c), six white-light-emitting diode illumination sources (d), complementary metal oxide silicon (CMOS) chip camera (e), two silver oxide batteries (f), a UHF band radio telemetry transmitter (g), and an antenna (h) (published with permission from [96]).