Snow Peak offers double wall titanium mugs with and without handles. I put the H200 inside the H450 with plenty of room to spare with a rag to protect each. Per the Snow Peak site they state the H450 can nest in the H600. Or you could nest the M300 in the H450. You could also nest the H600 into the H860 or M600.
Here's the info: http://www.snowpeak.com/tableware/cu...ug-tw-121.html
1999 Toyota 100-Series Land Cruiser...not nearly stock
2009 Kimberly Sports RV 'King of the Offroad' trailer: Sadly gone but it sponsored some of the best memories of anything I've ever owned!