These are commonly used for tasks such as reading, writing, or doing hobbies. This is especially for extended near tasks. Since there is a fixed distance between the lens and the object you are looking at, accommodation is required so you should use your reading glasses if you have one. This causes less fatigue because the magnifier rests flat on the page. However, it is not a hands free device, and it is not that portable. Children have and easier time using stand magnifiers.
Perfect for tasks where you need both hands like sewing, knitting, or other hobbies. This also provides a large field of view. Magnification is usually 2x but some have an additional bifocal lens of about 4x magnification. The cord that hangs it around the neck allows you to adjust the distance.
Hands free stand magnifier attached to a gooseneck lamp