These USA Kilts flashes are 5.5" tall and have elastic which wraps around your calf and attaches with metal clips on either end. They're also adjustable, so one size fits all. They're made of soft Poly Wool blend, so they hang nicely.
Flashes are adjustable elastic garters that help to keep up your kilt hose. Pull up the hose all the way and wrap the garters around your leg, just above the widest part of your calf. Attach the metal clips on either end of the garter and fold the hose back down over top of the elastic. Roughly 2.5" to 3.5" of the flashes should be visible from under the turned over hose top.