The EXFO FLS-110 is an Optical Polarized Source that offers CW and 2 kHz modulation for fiber identification, complete status indicators, low battery indicator and an auto-off function. The unit is housed in a sturdy, waterproof case surrounded by a shock-absorbing holster that protects the instrument in tough field conditions. Choose between the 1310 nm or the 1550 nm LED models. Both units feature high and low power levels to maximize battery life.