REASONABLE DESIGN: The CYTGOUPER bedroom door lock of the heavy-duty high-grade safety door is reversible, making it suitable for installation on left or right-handed doors INTERNAL LOCK KNOB DESIGN: Equipped with a unique internal door lock, which can be opened through the external keyhole. You can use it with confidence PLATING: The door handle set is frosted after multi-layer plating. The material has stable properties, scratch , and no fingerprints LOW NOISE: lock bearing design, no noise, door handle lock to provide a quiet user experience. A great choice for you WIDE USE: The portable safety handle and deadbolt, are suitable for various wooden doors and bedroom doors with thickness: 3.5~4.5cm frames. This exterior door lock set is designed to be used for modern interior and exterior doors for commercial and residential applications.