This is the third and final installment of my series exploring the M600. In my first post, I endeavored to explore the differences between both the old and new style M600’s. The second post reviewed those pens from the two different eras in a head to head comparison. For this post, I wanted to focus on another member of the M6xx family, one that defies the usual styling of the series and makes it somewhat of an oddity in the line-up. The pen up for review here is the M640 Mount Everest, released in 2008. This pen is part of the “Beauty of Nature” series which is composed of six pens in total released from 2007-2011. The theme behind these pens is centered upon celebrating the beauty of the natural world around us. What makes this series somewhat unique is that there are several departures in design from most of the other pens in the Souverän series, regardless of model, which I will try to highlight below. This departure in design has polarized some of the fan base as many have found it difficult to embrace certain design elements. The pen being reviewed today is from my personal collection but this review should be able to be generalized to all of the pens in the series.