The Extech 461920 is a tachometer for speed measurements. It is suitable for safe, non-contact speed measurements (2 to 99,999 rpm) on rotating objects. For this purpose, the integrated laser is aimed (at a distance of approx. 50 cm from the target) at the reflective sticker attached to the object to be measured. The scope of delivery includes a 9-volt battery, a reflector tape and a user manual.