Thank you, Rafowell - most interesting stuff. One of the joys of ETS is the presence of "deep specialists" on things like signal mirrors, electrical stuff, et al - people who really are subject matter experts.

As far as signal mirrors go, I am a satisfied user. Living, working, and undertaking SAR in Arizona and southern California for most of my life, how could I be otherwise? Ounce for ounce, there are few things one can carry in the outdoors that are as effective. You don't use a signal mirror on every excursion, but when you do use it, it will usually be for a most important reason.