(EN) A child resistant closure apparatus that is easily opened by the aged and infirm has a container (200) having a push-tab locking device (300) that locks into place in a series of sawtooth projections (150) on an inner surface of a closure (100). The closure (100) is rotatably screwed onto the container (200) whereby the push-tab locking device (300) locks into one sawtooth projection (150). Screwing torque in the direction which would disengage the closure (100) from the container (200) is not permitted unless the push-tab locking device (300) is manipulated so that an end of a flexible arm (310) is removed from the sawtooth projection (150).