Should be easy to find but I'm having trouble.
Is the penetration total of invested devises un-affected by Auras? p.183 square does not list invested devises as impacted...
Has to be somewhere!
W
The penetration of an effect in an invested device, if any, is indirectly affected by the Aura in the lab where that effect was put into the device. While resistance against that effect is affected by the Aura around the resisting being.
If there is an action needed to use the device, that is not affected by the Aura in which it is performed.
Cheers
So in other words, Invested effects are immune to local Auras.
You could be in Hell and the object would cast with the same penetration total as if being in the Nirvana of Magic with a magical aura of 10. Only the resistance would vary in this case...
Does seems a bit off the general feeling of universal magic 
W
If you view it in the meta, a character has spent resources to create the item: Vis and time. In that other game would you nerf something a character spent gold on? And that's spending only the one resource of gold.
But generally speaking, an item might be made if one expects to cast a spell often in adverse auras to avoid the botch dice penalty. I don't see anything wrong with that as an item has its own limitations.
Nothing prevents a SG from having a few demons enact an Aegis-like effect on some places with high infernal Auras. It just wouldn't be the plain and simple Aura to dampen that effect in the device.
Cheers
As far as I can tell, no. It is still a magical effect, and as such affected by aurae.
This does not contradict One Shot's statement.
Effects in a device is potentially affected by 3 aurae:
- The Aura of the lab in which the device is created affectes the labtotal. This is static and noted in the description of the device.
- The Aura in which the device is used, modify the effective penetration. This is dynamic and calculated in the situation.
- The Aura in which the target is located modifies the resistance (if any) of the target. This is dynamic and calculated in the situation.
Yes, this gives an advantage to magical devices used in magical aurae. live with it.
As William has noticed, this is not stated on ArM5 p.183. And AFAICS there is neither a way to infer it, nor an in-game necessity for it.
If a magus uses an Arcane Connection to work a spell effect from his lab, with a magic Aura, on a creature in an infernal one, his penetration is helped by the magic Aura, and the target's resistance by the infernal one.
If a magus in his lab invests the same effect - likely with reduced range - into a magic device, and gives it to a grog to use on a target in an infernal Aura, it is similar. The penetration of the effect, if any was invested, benefits from the magic Aura in the lab, and the target's resistance from the infernal one.
The side effect of the HoH:TL p.107 Virtue Tethered Magic provides an extreme case of this symmetry: both the effect cast with an Arcane Connection and the effect from the magic item form an Arcane Connection back to the magus.
Cheers
Was there supposed to be an argument in there?
I saw a series of statements, but no argument as to why they would be correct?
Oh, William gave the argument already in his OP, and it is that simple that I did not care to explicitly repeat or rephrase it.
I now do so here: If the Aura at the location of an invested device were of any relevance for its penetration, that would have been stated on ArM5 p.183 box Realm Auras under the item Penetration. It is not, and there are no errata for it.
So either one can claim an oversight of the authors and an outstanding substantial erratum, or one has to accept the box Realm Auras as complete and correct.
The rest of my post Magical Items In Auras is an explanation, why the current rules of p.183 wrt Penetration of invested devices look plausible to me in the context of the ArM5 game.
Cheers
Firstly, my apologies if I came across as hostile, I was honestly curious about the origin of the argument.
I would now like to point to the last lines in the box on p. 183
While this does not call out enchanted devices, I've always assumed this to also be the case for devices, seeing as 'constant penetration is constant penetration'.
This also (to my mind) satisfies the statement that "The modifier shown apply to the effect an aura has on any supernatural act performed within it. (ArM5, p. 183) Emphasis mine.
It also satisfies my sense of balance, in that devices already have the advantage of not rolling extra botch dice for being in a foreign aura (rolling no botch dice at all).
That stated however, I do agree (on re-reading p. 183 a few extra times), that it doesn't actually say so.
Infact, devices do not seem to be explicitly mentioned at all.
I do not agree that this results in "Yes Virginia, devices are unaffected by being in foreign aurae, Merry Christmas!" - indeed if anything, to me that means it's underdefined.
Discuss is with your troupe, as with so many other things.
This phrase deserves some further consideration, as you quoted it.
Does - for example - a grog wielding a magic sword against an infernal creature in an infernal Aura perform a supernatural act? The grog would not think so, and neither would I.
Does a redcap perform a supernatural act, if she crosses an infernal Aura while protected by her magical ring, that bestows HoH:TL p.73f Aura of Inconsequence upon her? I shouldn't think so.
And after looking at these two examples, we can also accept, that a magus unleashing spells from his wand of abysmal flame against a devil in an infernal Aura does indeed not perform a supernatural act.
The characters in all these cases benefit from the results of supernatural work that went into their devices. But this does not make their acts, if any, in the infernal Aura supernatural.
"... any supernatural act performed within it" is just not a well defined and clear phrase. It doesn't need to be, as It takes its meaning from the surrounding text, where invested devices are not mentioned.
These would have to be listed at the verrry least in the last sentence of the rules box, making that "For mystical creatures and enchanted items, there ...". They are not, though - and in such a condensed rules text omissions are as significant as inclusions.
So you'd like an erratum. Right?
Cheers
The word 'act' is why I concede that mine is not the only possible reading
No, but arguably the sword does.
What sort of magical effect are we talking about? One which is activated on contact? Or something like Edge of the Razor, which is casts on itself each morning, before it entered the Infernal Aura.
The redcap does not, but the device arguably does.
However, in this case the device probably activated it's effect before the Infernal Aura was entered.
No, you state that. Infact, I don't even agree that the two cases are equal.
You're making assumptions and putting words in my mouth.
Again, the magus does not, but the Wand arguably does.
Said magus cast a (R: personal, D: Sun, T: Individual) Ward Against Demons before entering the infernal Aura. Would you modify the penetration of this, once he has entered the Infernal Aura?
See above.
Potentially. I would be more inclined to agree if there were not so many other examples, including CrIg guidelines where I'm routinely told that the omissions are meaningless.
Oh you know me too well, ofcourse I would.
Most of all, I'd like a consistent, clear rules set.
And I'm not getting an erratum any time soon, am I?
So I will say: Do as thou wilt at your table. In the light of this thread, I will discuss what we do at our table with my troupe.
Fine with me.
Cheers
Odd that after over a decade of play, 5 multi year campaigns, this simple thing pop up 
Thank-you all for the discussion. I think we have reached a balance of opinions.
W