An O2 system is a wonderful and inexpensive (and cheap!) addition to KR flying. I've done several posts on how I put mine together - too much material to re-post here so if anyone is interested in this subject please go to the KR archive and look for topic subjects (3) "High Flying" with sender as laser147 at Juno.com.
As Jeff said, after a long day's flying even at lower altitudes, the brain is not in it's best state for dealing with the challenges of the arrival and the landing in an unfamiliar environment. This is especially true when night flying. I put my system together after reading a Deakin article and to avoid the headaches I invariably got when going from near sea level to higher cruising altitudes. The other benefits are just gravy. The difference between my system and the ones mentioned on PofA thread is that I use a pulse-dose medical regulator. It has only one outlet, but I have a single-place airplane. For those with two seats, I doubt many KR flyers are carrying anyone when taking long cross-country trips at higher altitudes so a medical regulator would work just fine. The welding regulators mentioned in the PofA thread have the same disadvantage that most aircraft regulators do - they are constant flow, wasting approximately 3/5ths of the stored oxygen. Mike Stirewalt KSEE ____________________________________________________________ The #1 Worst Carb Ever? Click to Learn #1 Carb that Kills Your Blood Sugar (Don't Eat This!) http://thirdpartyoffers.juno.com/TGL3141/53c174bad681974ba0821st02vuc