Print in ABS or PLA with 25-30% infill. Recommend printing only the All file. The arm must be rotated to lay flat if printed separately. The arm, or the entire assembly if you print everything, must have support turned on. Push fit the arm into the two iPad frames. For permanent use, glue them together.
Has fun designing, printing, tinkering with 3D printed cameras (creator of Flyer 6x6, Clipper 6x18, funded by "Pinhole Printed" Kickstarter) and open source 35mm film to 120 spool adapter. @pinholeprinted