Combination Contact/Photo Tachometer (461895)

461895 Combines both contact (0. 5 to 19,999 RPM)
and non-contact (5 to 99,999 RPM) models for 
use in virtually all tachometer applications. 
Uses visible light for non-contact 
measurements up to 6in. 
(150mm) from target. 
Comes with wheels for linear surface speed 
(0.2 to 6560 ft/m; 0.05 to 1999.9 m/m) or 
RPM measurements, 4 AA batteries, 23in. 
(0.6m) reflective tape, and carrying case.
Rotation Speed (Contact): 0.5 to 19,999rpm
Rotation Speed (Contact) Max Resolution:0.1rpm
For more details please refer datasheet.