A Sargent Mortise Cylinder modified by Farmerfreak. Lock has 6 regular keypins of all the same height, stacked with serrated pins of different heights making the different cuts. Then it has stacked serrated T pins for drivers. A hell of a lock to pick. Great job making it Farmerfreak. Thanks to Kokomolock for sending it to me. Thanks for watching. Check out www.keypicking.com