These parts are to augment the DNA Designs upgrade kit for Transformers Combiner Wars / Unite Warriors Devastator, to lock the upper arms together to prevent movement at the original shoulder joints.
The new parts simply clip to each figure and then peg into a 6mm hole in each DNA Designs shoulder piece. The two parts will be printed with a sprue connecting them to reduce cost.
Photos are from my own Prusa i3 MK3 3D prints, not Shapeways prints.
Printable STL files for this item are available for purchase on Cults -
click here.