Constructed to deter attack from sawing and hammering, both units are also highly weather resistant and inconspicuous. Both units are a good size and can accommodate all types of standard key including five lever locks, cylinder locks and car keys. Rust free for outdoor use and easily mounts to most surfaces.The units have a wide variety of useful safety applications, including carer access and remote location access control, without the need to issue large numbers of keys, or indeed to replace hundreds of locks in the event of compromised keys.