Material
The inside of the jacket is lined with a thin flannel lining. This provides additional warmth and feels very comfortable against the skin. The jacket impresses with its 3-layer Gore-Tex material, which makes it very robust and both waterproof and breathable. I tested it in heavy rain, snowfall and strong winds and the jacket kept me reliably dry and warm. The jacket definitely impressed me with its robustness, both in terms of weather protection and direct contact with stones, mountain and ski equipment. There are no signs of wear and tear. Compared to other hardshell jackets, it is relatively light. However, due to the robust material, it is a little stiff when folded up if you want to stow it in your rucksack. In terms of pack size, I don't think it's ideal, but I don't have the same expectations of a hardshell jacket of this type.
Pockets, fasteners and hood
The Sentinel AR has two large pockets on the right and left outside, which are fitted with a WaterTight TM zip (water-repellent). It also has a lockable pocket on the outside of the left upper arm, which I find very practical for a ski pass. Inside there is a slightly smaller closable pocket, which is ideal for a mobile phone. There is also a larger mesh pocket on the inside. This is ideal for storing thin gloves, buff, energy bars, mountain map, mobile phone, money, thin shirts, etc. I like the fact that I can open and close the pockets even when wearing thicker gloves. However, the hip belt of my backpack runs right over the outer side pockets, so I hardly ever use them with this backpack. I would find a slightly higher pocket between the chest and hip belt practical.
I think the ventilation slits under the armpits are great. There are also water-repellent zips here, which can be opened from about the elbow to the waist. Especially on very windy days I like to wear the jacket on ski tours on the ascent and ventilation slits are simply a must for me.
The hood is helmet-compatible and also has an adjustment option at the back. However, I hardly ever use the hood when I'm wearing a helmet. Without a helmet, it's a bit big for me, despite the adjustment option. I find the reinforced hood peak at the front practical.
As already mentioned, the jacket can be adjusted at the bottom of the waistband, at the hands and at the collar. This meant I could always adjust it depending on the conditions. The Velcro fastener on the hands in particular is easy to use when wearing gloves. I like to wear the jacket over my gloves, which is easy to do with the adjustable Velcro fastener. The integrated snow skirt is also a big plus for the jacket. This can be closed with two extra press studs. There are also fasteners on the snow skirt to attach matching ski trousers to the jacket, which I personally find a little superfluous. The snow skirt cannot be removed. However, I don't see this as a disadvantage as it doesn't bother me when it's not in use. I also often find the fastenings on detachable snow skirts annoying when carrying a backpack.