Want to make sure that your door knobs match on both sides of your miniature doors? Then this is the answer. Drill a hole through the door, insert a knob and thread through one side and thread the other side on. Dimensions, each knob : 3/16"L x 3/16" diameter. 1" to 1'. 1:12 Scale. This is sized for a dollhouse. Detailed scale model for adult collectors. Not intended for children under 14.