With a power meter or multi tester for free features: \n \nlightweight, portable and economical, lightweight, portable and economical, easy to use, no tedious learning process, fast test and large lcd displays all measurement information, bilingual operation: display in simplified chinese character or english, backlight function supports testing work at night, \nmeasure the length and defects of coiled optic fiber, large memory capacity (300 test curves) \nrs-232 /usb data upload port, interchangeable fiber-optic.