JW3306B Optical Fiber Identifier can quickly identify the direction of transmitted fiber and display the relative core power without any damages to the bended fiber. When the traffice is present,the intermittently audible tone is activated. The JW3306B optical fiber identifier alsor recogize the modnulation like,270Hz,1kHz and 2kHz . When they are used to detect the frequency, the continuously audible tone is are four adapter heads available: 0.25, 0.9, 2.0 and 3.0. The JW3306B optical fiber identifier is powered by a 9V alkaline battery .