The Fieldpiece SRPM2 Optical Laser Tachometer is a non-contact tachometer that measures revolutions per minute on any spinning surface. The Fieldpiece SRPM2 is designed to measure RPM or total count (total number of revolutions) on air conditioning and heating system blower motors and fans. An RPM reading out of spec can tell the user that the wiring may need attention or that a motor is not running at maximum efficiency. The Fieldpiece SRPM2 Tachometer works up to four feet away and includes reflective tape required for testing.