This is a 4m ALC (male) to LC (male) black simplex riser-rated outdoor fiber patch cable. OS2 is a standard single-mode optical fiber commonly used with wavelengths of 1310nm and 1550nm (9/125 microns) and has a maximum attenuation of 1dB/km. The OS2 standard is defined in ISO/IEC 11801. This optical fiber nonconductive riser (OFNR) cable is best suited for use in exterior fiber-optic applications. A simplex cable is a single strand of fiber that works best with bi-directional transceivers as well as other single-transmitting devices. Our patch cables are 100% compliant for all of your networking needs. Our products are guaranteed by federal law to not affect or void OEM warranties.