Bilock, high security deadbolt. Bump key proof, pick resistant, drill resistant deadbolt.

• High Security Tested 
• Bump and Pick Proof - Drill Resistant
• Extreme Attack Configuration
• Patent Protected in the US and Canada
• Double Acting Security - Nine pin chambers and two side bars
• Over 16 Million Codes per Keyway
• Unique Double Row of Pins
• Strong Nickel Silver Keys
• Twenty One Fashion Key Head Colors 

This deadbolt has two cylinders, you need key to open and lock from both sides of the door.