With the adequate production capacity and total quality management, a wide variety of sfp transceivers are available with different rates(155m, 1.25g, 2.125g, 2.5g and 4.25g) and transmission distance(from 550m to 120km). Details about one modle of atop's sfp transceiver here. Ap-s31121-3cl20 1.25 gb/s rohs compliant long-wavelength Pluggable sfp transceiver Product features Upto 1.25gb/s duplex data links Hot-pluggable sfp footprint 1310nm fabry-perot laser transmitter Duplex lc connector Rohs compliant and lead free Upto 20 km on 9/125 Metal enclosure for lower emi Single 3.3v power supply Low power dissipation