Remake of example 40mm cap with version 2

Customized version of http://www.thingiverse.com/thing:1757352

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=1757352

This is a remake of a test/example cap perviously made with the earlier version for comparison. It shows the thicker retainer tabs, smaller corner gaps, and changes to the recess hollow generated by the newer version. Compare this item with test custom plug/cap for square tube.