Upgrade your Stack-On or Sentinel gun cabinet with the Armstrong Stack-On Replacement Lock. This direct replacement key lock is designed to work with current models of Stack-On and Sentinel key locking gun cabinets. Please note that this replacement lock is not compatible with older cabinets that use tubular keys, smaller personal pistol boxes, or units with dial or electronic combination locks. Be sure to check your cabinet's model number and compatibility before purchasing this replacement lock.