My Backpack has a loop at the bottom.It is not part of the compression straps.It just hangs there.A single loop.What is it used for?l do not know what it could even be attached to for slinging something up...

Is it maybe a loop for attaching a gutstrap? A gutstrap is an auxiliary belt that secures the lower part of the pack from flopping against you.

Use it for anything you want. Hang extra water there. Or your cup. Or your knife. Or your camera bag. Or whatever. When your top loop breaks, you will still be able to hang the bag up, using the bottom one! Perhaps you could run a strap through it, and secure it around your waist for added security.

when l wash my daypack out, l use it to hang it upside down and drip dry.~~~*<>{

l am thinking it is an ice axe loop. Unless you're into mountaineering or glacier travel it is not something you will ever use for its intended purpose

Haha All my were giving..so l say, depending on who made it, you can normally find some literature on the packs on the companies website.

But l think that most companies add loops to hang things off of,,,,whether it be an ax or a pot. l use mine for pot and cup.

its an ice ax loop.

It is an ice axe loop. You use it to attach an ice ax to ur pack. Although many manufacturers have to loop on the bottom to run the axe through, they do not have a way to attach the upper part to the pack. l think this is odd.

How to use the ice axe loop (from the Wikipedia article below):

''Many backpacks designed with mountaineering tasks in mind will include at least one ice axe loop, mounted near the bottom of the vertical surface farthest from the wearer, each of which can secure one axe to that surface when it is not needed. These loops r effective, but their use is counter-intuitive, & often hard to grasp until experienced:

The axe must be held with head up, & adze rather than pick pointing away from the vertical center-line of the pack, while the shaft is lowered through the loop until the pick & adze rest on the loop. This sounds illogical (and looks so, if correctly executed) since the shaft appears to be positioned to flop around against the pack wearer is legs, or the spike to stab them.
These problems resolve when the procedure finishes with rotating the axe 180 degrees, with its head as axis: this moves the spike away from the pack to horizontal, & then upward to vertical. The center of the loop is then just above the axe is head, instead of below, & the adjacent portions of the loop wrap under the pick & adze respectively.
Securing the shaft against the pack near the top of the pack makes the spike point fairly straight up, where any hazard it might offer is at least visible; the pick is flat against the back of the pack; & the short & relatively dull adze sticks out little if any beyond the side of the pack.''