Salsa Alternator 1.0 and 2.0 UDH Kit for flat-mount brakes. - This Alternator Plate set works with all Alternator 1.0 and Alternator 2.0 compatible Salsa frames to allow the use of SRAM Full Mount derailleurs or SRAM UDH. - Fixes wheel in rearmost Alternator plate position (17mm back) - Native 140mm flat-mount disc brake compatibility - Includes required upper non-drive side bolt (choose 16mm or 18mm length to match frame thickness) and lock nut. All other hardware is re-used from current plates or can be purchased in the Alternator 1.0 or Alternator 2.0 Hardware Kit. - Requires a 12mm thru axle with 1.0TP and either a SRAM UDH or SRAM Full Mount derailleur (not included). Consult the Plate Kit instructions for recommended axle length based on the frame hub standard. - Engineering Identifier Number: 06-004163