An improved child-resistant closure for dispensers of liquid medicaments, the closure being of a two-part construction. The closure has an outer cap with a quantity of shoulder lugs and skirt lugs and an inner cap with a quantity of shoulder lugs and flexible beams. The closure has equal quantities of shoulder lugs on the inner and outer caps, equal quantities of skirt lugs and flexible beams, flexible beams having an arcuate underside, shoulder lugs having a depth to prevent hyper-flexion of the flexible beams, and an ideal overlap when the faces of the shoulder lugs are aligned. Additionally, provided are methods for attaching and removing the cap from a pre-existing bottle.