I purchased a Cammenga Model 27 because it is NOT liquid filled. Silva etc are good for general use, but beware of their inherent lack of robustness. If push comes to shove, use a baseplate compass to obtain bearings on a map, but I for one can do it faster with a protractor. Takes practice, but practice does make perfect. <img src="/images/graemlins/wink.gif" alt="" />