Customized version of http://www.thingiverse.com/thing:63731

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=63731

Using the following options:

text_font = Letters.dxf
text_inside = true
text_height = 2
text_enabled = true
main_feature = 0.5
text_engraved = true
ring_size_us_can = 6.5
smoothness = 20
text_spacing = 1.1
text_depth = 1
text_itself = Custom Ring USA sizes
main_wall = 2
cs_shape = cs_rounded_scallopped_rectangle
main_depth = 5