The backpack as such is relatively simple but not completely minimalist like some other "ultralight" backpacks. There are elasticated straps in the main compartment that help to keep the probe and shovel parts in place. Of course, this does not fully achieve the tidying effect of a separate safety compartment, but the straps prevent the shovel handle and probe from flying around loose in the backpack. In addition to the main compartment, there is a smaller goggle compartment at the top of the backpack, which is also ideal for other small items. There is another small zip pocket on the hip belt, which I personally don't use.
The backpack also has two ice axe holders (loops at the bottom, Velcro fastening system at the top for the shaft), another loop at the top that can be used in combination with one of the lower loops as a diagonal ski holder, as well as daisy chains - a removable strap system for attaching a snowboard or other items to the outside of the backpack. A helmet holder can be purchased separately, but is not included. I usually attach my helmet to the Velcro loops on the ice axe holder. All the straps and loops on the outside of the backpack can be removed or stowed away, which I like. The leg loop has its own "garage" into which you can stuff it with one hand if you don't want to use it at the moment. There are the usual openings for drinking tube systems and the buckle on the chest strap is not just a buckle but also an emergency whistle.
Test
Before first use, the cartridge must be installed and the airbag system checked. The cartridge should not deviate from the specified weight by more than 5g. The airbag system must be "activated" - you must check whether the pin located above the trigger mechanism is in contact with the mechanism or whether there is a gap between them. If this is the case, the system is returned to the active position using the "reactivation key" supplied.
In order to get used to pulling the handle and to get a feel for how much force is required for a release, test releases can and should be carried out without a cartridge. Simply pull the handle without the cartridge fitted. After each pull, the system must be reactivated using the key. The key is screwed into the cartridge thread instead of the cartridge. I probably didn't fit the spanner properly the first time and, as it is made of plastic, the thread of the cartridge holder (metal) damaged the spanner a little. It still works, but you should be a bit more sensitive when using the spanner than I was at first.
I've now used the backpack on around 15 days, mostly on day ski tours and occasionally for freeriding in the ski resort. I haven't had to deploy the backpack in an emergency yet and of course I hope it stays that way. The option of test releases without a cartridge seems sensible and important to me.
As far as the backpack as such is concerned, I am particularly impressed by the carrying comfort. Especially when you think back to the first airbag backpacks, a lot has really happened here. As a representative of a new, modern generation of airbag backpacks, the Reactor UL 25L scores points not only with its low weight, but above all with the well thought-out options for customising the size and height of the straps and release handle. The backpack sits compactly on my back and doesn't get in the way on the ascent or descent. The buckles on the hip and chest straps are easy to use and do not loosen. This was often a problem for me with previous airbag models, especially with the hip buckle. I also find the back padding and the ventilation system (holes in the padding) to be very successful - very comfortable to wear.
