Sorry, off on hols last week!
The foam strips are in our Alta & Alta II walking jackets, our new Pájaro 'country' jacket, and our High Mountain Aspira Smocks & Jackets (not in our multi-activity jackets/ smocks). They serve 3 purposes:
1. When wearing a rucksack, they hold the rucksack away from your back, allowing the Pump Liner to continue working without compression, to keep the weather out and, more important, to continue to move perspiration;
2. They make rucksack-wearing more comfortable as they provide padding and spread the weight;
3. They create a channel of air down the centre of your back, along your spine, the sweatiest bit of your back, which makes for much greater comfort.
I'll try & ensure that this appears in the jacket features where possible - we do run out of room to put everything in (and admittedly, if we are not careful, we take for granted what people know because we are too close to it!)