The titanium material frequently used for solo gear is designed as a double wall structure; the products are made in a variety of sizes to enable easy stacking. They are designed for easy grasping without handles. The H300 Seppou Stacking Mug is the second smallest of the five tall H-series mugs.  The H200 or the M150 can nest in it.  It nests in the H450 or the M300.