Expertly designed with the needs of professionals in mind, the Jonard Tools FLS-50 Optical Light Source includes FC, LC, and SC adapters for direct connection to UPC/PC FC, SC, and LC fiber connectors. Its highly stable output power and wavelengths, along with its four different modulation options (CW, 270 Hz, 1 kHz, 2 kHz), make it the ideal choice for single mode fiber measurements at either 1310 or 1550 nm wavelengths. The unit's flush button design prevents dust from entering and a shatter-resistant sleeve offers protection from falls or other damage. Plus, the backlit LCD screen provides a clear display perfect for use in dark environments. The kit also comes with two cleaning swabs, three AA batteries (required for operation), and a convenient storage pouch.