This is the Assa Twin 6000. The original in Assa's line of side pins locks. As you see this lock is unusual in that all the side pins are the exact same and its the side bar and the key biting that actually form the sidebar coding. The successors to the Twin 6000 are different in that they changed to finger pins instead of side pins and some have vertical serrations instead of horizontal. This is a great lock to learn how to pick side pins on as it requires a great amount of control on the tension. You can see in the pic that the driver pins are the old style Assa pins.
