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 a spectroelectrochemical cell UV-vis adapter with a porous electrode that can be printed on a dual extrusion 3D printer and used in a typical UV-vis spectrometer. The two .stl files can be merged by the slicing program to generate a single object to print with different materials. We have printed the electrode part using both ProtoPasta (https://www.proto-pasta.com/products/conductive-pla) and BlackMagic (http://www.blackmagic3d.com/default.asp) PLA-composite 3D printing filaments. The adapter portion was printed using either natural PLA or black PLA.