This solid additional lock with a knob and key makes your windows more secure. Your windows need to be safe. That much is certain. Make it difficult for burglars with this sturdy additional lock. The extra security lock is suitable for windows made of aluminum, wood, and plastic. The claw locking double bolt made of steel can withstand a pressure of over a ton. The lock is conveniently closed with a knob. A key is required to open it, and two keys are included in the package.