Washers are a common fastening element in hybrid ESF and circular ESF frames. Like many fasteners in these frames, they are available in two basic sizes for mini and standard size CESF/hybrid ESF frames as well as different styles.

Used as a mated pair (nut and washer) for adjustment of a hybrid rod or threaded rod angle - approximately 10º range of motion

Provides needed fill or offset during frame construction to maintain wire alignment; often used to offset a third wire being placed on a ring. 

Allows capture of fixation wires to rings (or rods) at locations otherwise occupied by supporting elements. Also utilized for drop-wire technique.