2 brief seconds, but WHAT seconds! I was opening my Zulu trapper for the umpteenth time, and figured that's about how long it takes.
When you start to open it, it's firm but pleasant. It tells you it'll stay closed when you pop open your 'chute, but it won't break off a chunka fingernail when you open the knife, even when that nail is 65 years old and brittle. Then, it pops smartly into the half stop, and waits there until you change your grip, and then a pull gets it accelerating into the open position where it thunks home impressively, saying "I will not move unless you do something terminally stupid!"
The action of the blade is regulated to act correctly every step of the way!!
Same goes for closing it. You've got leverage when it's open, so you can enjoy it's firm spring in that position, and the half stop provides the pause point, because you do NOT want THIS blade nipping a finger! It was born to CUT!! It then snaps politely but firmly home, eliminating that destructive "thwack" that is completely unnecessary, sparing the equipment.
This knife is a work of art you can enjoy with your eyes closed! It's function is every bit as beautiful as its appearance.
You can all probably tell the love affair continues. Stop me when it gets boring.