I printed this at 0.1 layer height to make sure that the intricate little clip printed properly. That said, I printed an older revision at 0.2 and even 0.3 and it seemed to work, so I expect this one would too. I used PLA, though I'm sure other materials would work. The original piece is ABS.
It is best to print this on edge, with the clip facing to the left or right hand side of the bed. (It should be oriented correctly in the provided STL)
Although this does make it harder to print than if you lay it down flat, the clip is just too weak in that orientation as the layer lines end up being in the same direction that it needs to flex. Try adding a raft if necessary, and make sure your nozzle is nice and close to the bed to ensure proper adhesion.
This will need supports. I used the zig-zag type. Again, be very careful of the clip when removing the supports.