here is the link to the posi lock..Search Results by 4 Wheel Drive Hardware
.. and yes it eliminates the vac system which when u engage ur 4 wheel drive moves ur shift fork and engages ur front driveshaft. with the posi lock it looks like an ejection button that sits inside, (i mounted mine to the dash down by my left knee) and instead of the vac system pushing and pulling the posi lock pushes and pulls the shift fork into position. It's more than worth the money I would recommend it to anyone still using the stock vac system. I actually pulled all my vac lines out and plugged them. So it also cleaned a lot of the clutter up in my jeep.