“”””””I can’t get my head around this as it goes against how I have worn jackets my entire life! So you are bare chested under the jacket? So when you go inside and leave your jacket at the door..?””””””
Yep – dump tshirt at door put Extreme jacket on. It works in a wider temperature range than if you wear a base layer as it allows quicker dumping of heat. You also dont get any feeling of being wet if its seriously hammering it down as there’s no base layer stuck to you – its the pile directly against your skin working to pull moisture away by capillary action.
I will however generally wear the Hydrogen with a base layer just because its not as thick/warm as the extreme.
If you read the small print of Buffalo its how they recommend them worn.
I googled this subject to death as I was sick of membranes not working but couldn’t get my head round not wearing anything underneath Buffalo/Montane/Pile&Pertex
https://www.ukclimbing.com/forums/gear/wearing_buffalo-180754