Feature: 1. SUPPORT 1310/1550NM: Mini fiber optic power meter supports 1310+1550nm, powerful, dual wavelength handheld stabilized light source for testing optical fibers. 2. 2.5MM UNIVERSAL INTERFACE: Optical fiber light source comes with a 2.5mm universal connector for a wide range of applications and a silicone dust cap to protect the connector from damage for longer life. 3. 4 MODULATION FREQUENCIES: Fiber optical power meter has 4 output modulation frequencies (CW, 270 Hz, 1 kHz, 2 kHz) at 1310 nm and 1550 nm for stable and reliable output. 4. BACKLIT LCD SCREEN: The screen comes with a backlit display to provide a clear viewing display, perfect for viewing in dark and low light environments, and is equipped with an LED light for illumination in the dark, allowing the device to be used normally in the dark, thus improving work efficiency. 5. SHOCKPROOF AND DROP PROOF: Optical light source is made of ABS material and features a protective silicone exterior that is shockproof and drop proof to minimize collision damage and extend the life of the device from drops and other damage. Specification: Item Type: Optical Light Source Material: ABS Wavelength: 1310+1550nm Output Power: ≥-5dBm Optical Connector: 2.5mm Universal Power Supply: 2 x AAA Battery (Not Included) Output Stability: ±0.05dB/15mins, ±0.1dB/8h Modulation Frequency: CW, 270hHz, 1kHz, 2kHz Product Size: 130 x 35 x 65mm / 5.1 x 1.4 x 2.6in. Package List: 1 x Optical Light Source 1 x Instruction Manual Download Guide