An adapted version of the popular squashball feet to be able to fit on double v rails (Like on the Ender 3).
Print with the cup facing up and the rails facing down.
USE SUPPORTS! I recommend adjusting your support angle so that it only supports the base.
UPDATE 25th Dec 2018 - Added a version with M3 bolt holes on the end to be able to T nut to the rail for added stability.
UPDATE 22nd Dec 2018 - Added more space between the rails as it was a little tight.