All Detex mechanical clocks have been discountinued.  After 130 years, it's over.

This is a very suitable replacement:  The Amano PR600.  Click on this line.
                             

Why?  
    1)   It is mechanical.  This is what you are used-to.
    2)   Better-yet:  Electro-Mechanical.  Quartz Crystal Controlled Movement
           Quartz crystals are essentially tortured by adding DC voltage. 
          They then scream out a set frequency.  A small chip reads it and compensates.
          This then runs a motor.  By nature, it's accurate. Very accurate.  
    3)   No winding.  Replace a standard "C" cell 1-2x a year.
    4)   Steel station keys, use your existing Detex station boxes or use the ones
           that come with the 15 station kit.
    5)    Accurate:  Does not need periodic servicing. It reads an electronic signal,
    6)    Cheap to keep:  One box of 10 report tapes typically lasts a year.  
           Unlike the Guardsman, it only advances when you twist the station key in the reader.
    7)    Not made in USA, not made in China.  It's from Japan.  Home of VW and Toyota. 
    8)    Service/repairs when needed, are done in Roseland, New Jersey 

Amano makes a machine that works the same way.

These are the reports: Click on the images to see the product page.