This replaces the limit switches for all three axis. It also acts as a filament detector sensor. This will fit CR-10 Small (300*300*400), CR-10 Medium/S4 (400*400*400), CR-10 Large/S5 (500*500*500) Printers, as well as the Creality Ender-2 Mini or Afinibot printers, including the A31.