The Adtran Rack Mounting Kit (vendor part 11971214F4, Millennium part 544553) fits the SDX 8305-20 chassis into a 23 in equipment rack for central office and headend installations. It matches the mounting ear spacing of the 23 in rack standard used in many carrier facilities, so techs are not adapting hardware in the field. Central office installation crews use kits like this to get access electronics racked and cabled on schedule. Millennium also stocks the 19 in version of this kit for standard telecom racks, along with the SDX 8305-20 OLT itself.