Monarch 6180-056 Optical Sensor, for up to 3 feet. Range from 1 to 250,000 rpm from Cole-Parmer United Kingdom
Amazon.com: DIGITEN 4 Digital Green LED Tachometer RPM Speed Meter + Hall Proximity Switch Magnet Sensor NPN for Lathe Conveyor Belt : Industrial & Scientific
DIGITEN 4 Digital LED Tachometer RPM Speed Meter+Hall Proximity Switch Sensor NPN Red : Amazon.in: Industrial & Scientific
G3X RPM Sensor, Slick Magnetos - Steinair Inc.
Replacement RPM Sensor – Stainless – Computech
Proximity Sensor high RPM Dia 8mm tip – industryparts.pk
RS series RPM and Rotational Speed Sensors | Hydrotechnik UK Ltd
Hobbywing, RPM Sensor, V-Bar system, Mikado - HOBBYWING North America