1. Door chains are commonly used on front doors as they help identify callers before the door is fully opened. Antitheft door chains provide more security from intruders and are less prone to damage when the door is forcibly opened. 2. Front door security locks are used as chain locks for front doors and provide the added benefit of a door lock. The front door can be fully opened from the outside by means of a key. 3. The smoothrunning function of the chain lock on the front door prevents the safety chain from getting caught unnecessarily or getting trapped. The interior of the door lock should not be a burden for you, as you won't have to worry about having to open it forcefully. They ensure your safety with additional door security functions. 4. Door lock chains are mounted on the surface, which means you can easily install them with just a screwdriver or drill. Front door locks are universal and can be installed on doors of any size.