Deuter has developed its own design of classic top loading packs with a lid that allows for extra volume when needed, and they have been using it for years in many of their backpacks series.
In short, the “+10” in those Deuter backpacks mean extra volume in liters, which you have with an extendable collar. In their smaller packs you will see +5 and in the largest +15. This is a feature that you have only in their classic designs with a collar and lid.
Why does this +5, +10, or +15 matter?
In the case of Deuter, these numbers are always in the official name of a backpack. I do not remember any other brand with such a practice. So many Deuter smaller packs with lid (but not all) have +5 extra liters of volume when needed, and larger packs offer the other two options.
This is convenient for several reasons. Imagine you have a 45 liters pack (one example is below), you can use it even for some day tours that require more stuff and also for overnight tours. When you carry bulkier items, say in a colder environment, you expand its collar for extra space.
Think about this also in the following way. You start a self-supporting tour where in the beginning you have more food and water. So you need a larger pack, say 55+10 or 70+15 liters with its expanded collar (examples below).
In time, the amount of stuff in your pack will reduce so you can physically reduce its volume for 10 or 15 liters. This may be just enough to make it compact enough and to stabilize the load inside.
What does this design include?
• Obviously, there is a collar and it is equipped with at least two cinch cords. You can see them in the pictures below in one of my Deuter packs. The lower cord is used when the collar is not expanded. The upper is in use when you expand the pack, in this case you keep the lower fully loose as in the picture.
There is also a top strap with a buckle that secures things in the collar. You can use it also to put your climbing rope on the top of the collar and to keep it safely in place.
• In order for this to work, the lid must be what is described as a floating type. This means it has two straps next to the usual load lifter straps, see the picture below. It can be adjusted and moved up or down.
In the following picture you can see how the top of the backpack looks when the collar is extended and the lid is raised and in place:
Examples of Deuter packs with expandable collars
The Deuter Aircontact Ultra 45+5L SL Women’s Fit Hiking Backpack shown in the picture below is an example of +5 liters packs. Its lid is completely removable as well. This is a version for women, hence the letters SL in the name, they also have a 50+5 version for men.
In this video you can see a bit more about this series from Deuter:
Here is one great example of a pack with +15 liters, the Deuter Aircontact PRO 70 + 15:
Yet another great example of this +15 liters type is their new series Deuter Aircontact X backpacks.
To conclude, the numbers +5, +10, and +15 in Deuter packs imply an expandable collar. This is something very useful and it adds a lot to versatility of packs from this brand. I have them several and I have been using them for decades.
This is their classic design, and the included lid, which is a part of this deign, usually has two pockets in it. Both elements together add to functionality of these packs.
Note also that Deuter is one of the top brands that builds gender-specific packs for men and women. So the letters SL in the name of one of the packs above mean ‘slim line’ and this means a pack for women.
For more texts of this type please check under the category Trail Gear here in the site. Thank you for reading, let me know if you have questions or comments, there is a comment box below. Have a nice day.