Petzl
Petzl FOOTAPE
Ascending a rope using only your arms is exhausting; using your legs, it's doable. That is the entire purpose of the foot loop: to transfer the effort to the muscle group that can support it.
What it is used with
The FOOTAPE was designed specifically for use with the ASCENSION rope clamp for rope ascents. It is a system accessory, not a standalone product.
The foot loop
This is the part that takes a beating: it rubs against the ground and bears the body's weight with every push. It is therefore reinforced and abrasion-resistant, and sized to accommodate all types of footwear—a foot loop that is too narrow for a thick sole is useless in the field.
Manufacturing
Nylon, reinforced stitching, and steel buckles. Steel rather than light alloy: for a buckle that adjusts under load, grip and wear resistance take precedence over saving a few grams.