Synology Rail Kit - Mounted Secures RackStation on a rack A. Mount post width must be equal to or greater than 451mm B. Panel width must be equal to or greater than 480mm C. Rack mounting depth: 570mm~720 mm (for 13-series and earlier 1U models) 21-series: RS1221+ 19-series: RS1219+, RS819 18-series: RX418 16-series: RS816 15-series: RS815, RX415 12-series: RS812(RP)+, RS812 11-series: RS411 10-series: RS810(RP)+, RX410 9-series: RS409(RP)+, RS409, RX4 D. Rack mounting depth: 570mm~810mm (for 14-series and future 1U models) 20-series: RS820(RP)+ 19-series: RS1619xs+ 18-series: RS818(RP)+ 15-series: RC18015xs+, RS815(RP)+ 14-series: RS814(RP)+, RS814