On the Monoprice Mini Delta the feed hose going to the extruder tends to get caught in the motors on occasion. This causes some very bad noises and prevents the extruder from reaching its home position at the end of the print. This clip helps guide the hose back into the proper position to prevent this from happening. The piece will clip onto the housing rail, no need to glue or screw it into place. Just be gentle when putting it into place so you don't snap the piece.
be sure that when it prints that you are getting solid pieces. One of my early attempts built with a hollow portion and it snapped while trying to install.