It is used to detect optical fiber breakpoints, for the construction and maintenance of integrated wiring, the production and research of optical components, and other optical fiber projects. and portable, easy to carry and comfortable to hold. Longer penetration distance, stable performance and long service life. 3 levels of brightness are adjustable, and there is a power signal light, pay attention to the power at any time. With LED light for easy operation in dark environment. 2.5mm universal pen head, detachable, easy to replace the pen core. Specification: Model: B3S05 Output Power: B3S05: 5mW operating hours: Interface: 2.5mm Output wavelength: 650nm Colour:black Material:plastic Package Contents: 1 * Fiber Optic Tester Pen Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.