It is a Z-trap with the push/pull trigger. If I had to buy again I would go with a different brand. I feel the spring is just to stiff and causes alot of broken bones. I have daggers with the same trigger set up but not a fan of the V shape spring. The dukes are nice once you get use to setting them with something stuck on the trigger. From what I have read the Z traps will no longer be made because the coon dagger got his patent on the trigger system which Z_trap copied.