Test for both single-mode and multi-mode, ST / SC / FC interface fiber optic cable, 10KM red light output, 650nm bright red light, LD emitter, 0mW output power, 2.5mm universal connector, 3-24V voltage range, -10~+60 operating temperature, 2Hz CW frequency, replaceable ceramic core design to prolong the lifetime, energy saving and lightweight, 2 x AA battery power supply, 175 x 26 x 26mm dimension.