This is an adjustable linear bushing with mount, for a Prusa I3 Y axis. Also depending on the style of frame used for your 3D printer there may be clearance issues.
This type of bushing helps with differences in printing tolerances by allowing one half to flex. The screw holes help hold the flexible half in position with the added benefit to adjust for wear.
Hole spacing 30mm
Adjustment screws are M3 - i recommend using grub screws if you have them.
Note: Needs to be printed at 0.2 mm layer height with a 0.4 mm nozzle.
7/19/2017 - uploaded just the bushing section, for people who want to mess with the design. OD is 18.70mm