If you mean the shoelace tied to a moving eyebolt swivel, it feels similar to a ball hook, but without much noise. The eyebolt is mounted to a ball bearing. With a large bag almost any small ball bearing would work, but for really lightweight bags a dry bearing is better -- these have looser tolerances and need no lube and spin very freely which is necessary to prevent the shoelace from twisting around on itself. I use 550 paracord instead of shoelace.