This is remix from a tinkercad file by 09rtse. https://www.tinkercad.com/things/iywhVFrWk8U-cupholder-expansion-for-mugs
I edited it to allow for it to hold my Yeti Rambler mug and knockoffs. It also fits regular pop (12oz) or energy drink (16oz) cans without having to remove the adapter.
yeti_cupholder_expansion_3.stl | 141.6KB |