Fiber Checker Pro, VFL with 2.5 mm and 1.25 mm connectors, is used for installation, maintenance, troubleshooting, and repair in fiber optic cables. It is designed to detect the continuity of signal transmission and cable breaks in fiber optic lines. The device operates in both single mode and multi-mode, as well as in plastic fiber optic cables. The visible range of the laser beam extends up to approximately 7 km. The Hobbes Fiber Checker Pro II emits a bright red laser beam at a wavelength of 650 nm through the connected fiber optic cable, either as a pulsed beam or a continuous beam, thus helping to locate faulty spots on the fiber optic cable or connectors. When checking for continuity, it is easy to test fiber optic cables even within a bundle of cables. Alternatively, a fiber optic link can be tested by bending a patch cable. Defective spots can be identified by the noticeable emission of red laser light at the point of failure.