1181-9050 KIT Z-Axis Encoder Scale For EZ Trak Early Version (W/Cantilever Arm) Or No 3rd Axis 

(Scale Dimensions are 10.375" OAL W/ END CAPS, 9.43" Between Mounting Hole Centers,  Body Dim = 1.12" H x .810" Thick)

(Actual full length travel = 5.75")

This Kit Includes Adaptor Cable