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Bubbles in compasses

You offer the Suunto MC 2G compass  . But there is also a Suunto MC 2G 6400 available . Is it the same thing ? 

Also, I have four Silva 15 Ranger compasses that each have air bubbles. Do you know if the Suunto warranty covers the Bubble problem with these expensive compasses ? 


Boyd Anderson

4 Replies

@Crash Thanks for reaching out!

Based on the specs on the Suunto Website, the only differences we can see between the MC 2G and the MC 2G 6400 are that the MC 2G 6400 offers a direction scale in mils and has USGS UTM scales, while the MC 2G has direction in degrees and has Metric UTM scales. The MC 2G 6400 is listed as a 'Military Mirror Compass' and has 'Rugged construction' whereas the MC 2G is listed as 'The Sighting Compass for Global Mountaineers' and is 'the advanced navigation compass'. It does not look like the MC 2G 6400 is currently in stock.

In regards to your Silva 15 Ranger compasses: Silva is a different company than Suunto, so you would need to reach out to them regarding their warranty. You can find their contact info on their Silva Warranty page here.

Hope this helps!

At REI, we believe time outside is fundamental to a life well lived.

I find it weird that one model says USGS UTM and another say Metric UTM, I think they are the same thing.  Yep, just read on the USGS web page about that,

Well, I do have several extremely detailed topo maps from germany/switzerland/austria/france (the alps), I never needed to compare their UTM lines with a US printed topo, but then again, the lines don't really need to match.  This is a weird rat hole to go down, I must be really bored this morning.


It's been my experience, that any gadget offering scale/template features are problematic, because they assume an exactly measured map print-out which would line up with your map's UTM points.

my point being, just think about how any set scale is going to line up with whatever paper map you use, and figure it out at home, before venturing out.

REI Member Since 1979

Thanks. The bubble issue seems to be common . I was hoping someone warranted against it . The notion of temp and elevation changes is nonsense . I have had compasses that developed bubbles with zero changes in either . Just setting in the drawer waiting to get back outside . Small bubbles are more cosmetic but large bubbles can interrupt the functioning of the compass and render it suitable for the retirement bend.  So what is an accepted limit on bubble size ? Who knows .  If you get lost then your bubble is too large .  A sad industry position on a troublesome issue.  


Regarding the bubbles, I've never had a liquid filled compass that didn't have or get bubbles over time.  They don't affect the accuracy of the instrument in any way. Usually formed by elevation and temperature changes. At the worst, they're might be aesthetically displeasing, but they don't hurt a thing.

Retired medical technologist and engineer
REI member since 1978
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