SFPs are compact transceivers which function as modular connectors. Available for copper (RJ-45) and for all common fiber modes, wavelengths and data rates, SFPs allow network operators to connect different interface types to the same network equipment, via an SFP port. The cost of cable upgrades is greatly reduced - preserving the investment in costly networking equipment, for the price of a relatively inexpensive SFP. More and more network equipment is being designed with SFP ports, to take advantage of this flexibility, and to take the uncertainty and guesswork out of expensive equipment purchases.