Abstract: A pulse transmitter for a liquid flow meter comprises an input shaft rotatably mounted in a housing and magnetically coupled through a wall of the housing to a rotor of the meter. A meanetic reed switch for electrical current interrupt is operated by a rotating magnetic member on an output shaft, the output shaft being connected to the input shaft by a pair of calibration gears. The input shaft has a pinion thereon, the transmitter including provisions for compound reduction gearing to a sleeve on the input shaft, the sleeve driving one of the calibration gears. The input shaft also has an upper magnetic coupling member for driving a visible indicator ball through a wall of the housing, the ball being confined in an external cavity by a transparent member.