Customized version of http://www.thingiverse.com/thing:56910

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=56910

Using the following options:

_bayonetDepth = 0.4
_insideDiameter = 27
_resolution = 120
_part = base
_topBottomThickness = 1.0
_partGap = 0.1
_minimumWallThickness = 1.0
_style = round
_interiorHeight = 25
_lipHeight = 3.0
_numberOfSides = 9