The general purpose of these designs are described in “Electrolysis Activation of Fused Filament Fabrication 3D Printed Electrodes for Electrochemical and Spectroelectrochemical Analysis”, which is published in the journal Analytical Chemistry. DOI:10.1021/acs.analchem.9b01331 This particular part is the "spectroelectrochemical cell" UV-vis adapter without the porous electrode. The adapter portion was printed using either natural PLA or black PLA (we recommend black).