Customized version of https://www.thingiverse.com/thing:5983067

Created with Customizer! https://www.thingiverse.com/apps/customizer/run?thing_id=5983067

Using the following options:

outSideLength = 66
outSideWidth = 58
outSideHeight = 31
fillHeight = 0
shellThickness = 3
ribThickness = 9
filletRadius = 4
splitFactorPercent = 60
showBox = 1
showBoxTop = 1
showBoxBottom = 1
showBoxCombined = 0