never mind i found it, im blind as a bat!...
I wholeheartedly agree, as it is the first thing I put in my standard P-Series guns.It should be all of them. It's not but it should be standard equipment because the reset on standard Sig's sucks.
Legions, Elites, Stainless Elites all have SRT's. Maybe some others.
I think they are referring to the FCU (a.k.a., frame) which is stainless steel as opposed to the grip module which is glass filled polymer.It appears that whoever is maintaining their website doesn't know the product very well.
I want one of those P320's with the stainless steel frames.