Zyxel SFP-SX-D. Maximum data transfer rate: 1000 Mbit/s, Maximum transfer distance: 21653.5" (550 m), Wavelength: 850 nm. Form factor: Plug-in. Safety: Class 1 Laser, CSA, TUV, 21 CFR 1040.10 & 1040.11. Width: 2.2" (56 mm), Depth: 0.528" (13.4 mm), Height: 0.491" (12.5 mm). Dimensions (WxDxH): 2.2 x 0.528 x 0.491" (56 x 13.4 x 12.5 mm)