It is a total of 6 inches long (15 cms) and the horeshoe is 2 inches wide (5 cms)
The disks at the bottom are not fixed, but rather they spin so that if the fabric is pulled it can rotate or drop about half an inch before it releases it (or creates a tear, this should not happen though)
It works like a clamp with the horseshoe moving downwards to release the pads at the bottom. The horseshoe is then pulled upwards till it reaches a groove and clamps on the fabric.
This type of skirt lifter was mass produced in the 1870s until the 1890s out of pressed brass. They are also an essential item for any fashionable lady seeking to protect the fabric in the train of her dress. These often have black woven ropes attached to the top that are then either clipped into a belt at the waist (for sports and cycling for more adventurous ladies) or looped around the wrist (for more graceful motions such as dancing).
I would love to find a more specific date for this skirt lifter. However, as it was a mass produced item it fails to have any datable markings. If anyone knows anything about this particular type of skirt lifter please feel free to let me know.