10GBASE-LR is a 10-gigabit Ethernet optical standard that operates at 1310 nm over single-mode fiber (SMF), supporting link distances of up to 10 km. It is typically implemented using SFP+ transceivers and defined under IEEE 802. Use in data centers, enterprise core networks, and telecom aggregation nodes. 10G still makes sense when downstream devices are 10G or when you need inexpensive, low-power uplinks that won't stress your cooling budget. It operates at a wavelength of 1310 nm and features an LC/UPC duplex optical connector. Compatible with the SFP+ MSA standard.