It's opened by squeezing the top portion of the tabs, located on opposite sides of the cap. To close, turn the cap until there is an audible "click." Applications include pharmaceutical and household chemical products.
Weatherchem Corp.: CR closure
A new child-resistant, senior-friendly closure called Top-Squeeze(TM) is available from Weatherchem Corp. (Twinsburg, OH). This PP, injection-molded closure is said to provide easier access when compared to other push-and-turn or squeeze-and-turn closures due to its half-turn opening method.