This solved my problem of my wine glasses being too tall for the top rack. Clip these onto the stem and then slide them onto your lower level dish rack uprights. It's super stable and has been through a number of cycles so far, still working great.ABS probably works best for the heat in the dishwasher...
V2 Added - put a wedge in the corner for extra strength - also added a single holder version as requested.
V3 - Made the uprights 2mm thicker for more strength
Made on Tinkercad.com
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