The Suunto KB-20 is a hand-bearing and floating compass that weighs only about an ounce.  But it’s not the size that matters here but rather the accuracy.  The Suunto KB-20 allows the user to sight and follow bearings with accuracy better than 1 degree.

The Suunto KB-20 has a scale graduation of 1 degree, a reverse scale for readings through an optical lens and regular scale for viewing from above.  It’s bright yellow so you aren’t likely to lose it even in the bottom of a dark bag and it has a lanyard to keep it handy. 

This little compass is so accurate it’s actually used in commercial applications.  It can function from -40 degrees F to +140 degrees F and has a self-cleaning capsule bearing.  It’s easy to read and therefore use.

It’s not cheap – MSRP is around $85 but you can find it for up to 30% less online.  This compass is not for those who point the bow in roughly the right direction and hope for the best.  This is for those times when precision is everything.