High Security. The SARGENT Keso® F1 Security System offers the building owner full control over field duplication of keys, highly pick resistant cylinders, expanded levels of master keying and a proprietary patented key system. With the Keso F1 cylinder, it is impossible to determine the configuration of the key system or its upper level master keys by examining the pinning configuration, providing the highest level of key system security available on the market today!  

Features & Benefits

  • Patented product* - can not be copied or supplied by others
  • Retrofitted to the original version Keso master key systems
  • Two lines of dimples (Line 1 and Line 2) can be added to the key blade - offers over 100 thousand usable combinations
  • Operates in existing old style Keso cylinders
  • Unique combination of pin lengths and positions
  • No chance for duplication
  • 6-sided F1 key is stronger than a conventional
  • Ideal choice for highly abusive applications
  • UL 437 provides a maximum level of pick and drill resistance
  • Available in removable core
  • F1 keys will operate existing Keso cylinders, but existing Keso keys will not operate Keso® F1 cylinders
  • Keso® F1 key is symmetrical and reversible

Strength & Durability

  • Cylinder has 12 pins unlike most cylinders with only 6 pins
  • Unique 6-sided dimpled key is much stronger than warded keys
  • Precise manufacturing and the absence of splits makes the cylinder highly pick-resistant


  • Compatible with existing non-patented Keso key systems
  • Key is symmetrical and reversible
  • Removable core versions available
  • UL 437 Version available for mortise and rim cylinders
  • Temporary Construction core available


  • Up to 7 levels of master keying available
  • 100,000 different key pin patterns available within any one installation
  • Keso® F1 cylinders can be retrofitted to original Keso cylinders
  • Keso® F1 key will operate existing old style Keso cylinders


  • Patented protection for both key and cylinder
  • F1 keys can not be legally duplicated
  • Owner's authorization required for any F1 keys/locks
  • Pick resistance
  • Impossible to determine configuration key system by examining pinning configuration
  • Every key stamped with the key system registration # and with key #. Key sets also optionally available to be stamped on keys and/or cylinders plug faces

Ideally Suited For

  • Government Buildings
  • Police Stations
  • Hospitals
  • Schools
  • Warehouses
  • Colleges
  • Detention Centers
  • Psychiatric wards
  • Any high abuse application

For more information about SARGENT Keso® F1, please click here.