The Cisco SFS 3504 chassis ships with a rail mount kit (SFS-3504-RMK). The rail mount kit is sufficient to mount the Cisco SFS 3504 chassis. For customers requiring a shelf-style support, the Cisco SFS 3504 chassis is also compatible with the SFS-7008-RKIT rack mount shelf. This shelf accommodates racks from 24 to 30 inches (60.96 to 76.20 cms).