Sock Toppers are a lolita accessory that is a bit like a wrist cuff for your legs. Sock Toppers are a ruffled elastic circlet of lace that is intended to be worn at the tops of a pair of socks. It both helps hold the sock in place, much like a garter, and also adds a little extra ruffle of lace along the top of a pair of socks. A Sock Topper might be used instead of simply buying a pair of Lolita socks with lace at the top to make multiple plain pairs of socks more loliable.
Sock Toppers are more commonly seen in the Old School Lolita style, as socks with ruffles of lace at the top have since fallen out of fashion.