Defender Security E 2498 Vintage Style Door Knobs w/Satin Nickel Finish, 2-1/4 in. Outside Diameter, Steel This set of round knobs is used indoors with old style mortise lock sets Features 2-1/4 in. outside diameter knobs with 1-3/4 in. projection and 17/64 in. x 3-1/2 in. square spindles Satin Nickel Finish Steel constructed knobs