Top Rated: Scramble Tower 11L Full Zip Pack Extender (9.1 / 10)
Category: Backpack Side Pocket (Rucksack Side Pouch)
Our favourite packs are the Karrimor SF Predator 30 and the Blue Ice Warthog 40 (review coming). The Scramble Tower is the perfect companion for both of these and pretty much all 30L+ packs on the market. The only packs that won't play well with the Tower are those with permanent protruding side pockets or over-designed clutter on the side - but basically if your pack can hold a closed cell foam sleeping mat, it very likely will host a Tower.
We looked at a number of 60L packs and noted their weights. If you add a couple of Towers to the Blue Ice Warthog for example, you end up with a very comfortable, agile, incredibly tough 60L pack that weighs just 1350g (much lighter than the vast majority of 60L packs out there). Since testing, the Scramble team have dumped their pouches, pockets and heavy duty dry bags. I have to admit I've done the same, it's basically solved all my load extension issues and has meant that as long as my 30/40L pack of choice can handle the load (without becoming uncomfortable) I can seriously extend its capacity and in so doing extend my range, especially in Winter when kit is always bulkier and heavier and at the same time reduce my overall pack weight.
Furthermore, it enables buyers of new packs to consider a different approach; being able to opt for a tough minimalist climbing pack knowing it can be configured and extended for touring / backpacking with the use of a Tower or two. The outdoor industry might not appreciate selling less packs, but at Scramble we've always had the view that one or two packs should really suffice (a small 20L pack and a 30/40L pack that can be extended to around 60L). The Tower makes that ideal a genuine reality.