This is heavy duty hydraulic "Lever Lock" e-brake setup. Depress your brakes, switch it into "Lock" and release the pedal. Kind of like a line-lock but it stays engaged mechanically. I got this from Trans-Axle and it is originally used for dump trucks and other large vehicles as a rendundant e-brake system. It has an electrical pressure switch as well as the hydraulic switch. You can use the electrical switch to sound a horn if the pressure on the brake side of the switch goes to low. I wanted to use this create a e-brake setup for my old 4 wheel disc brake setup on my off road truck. Perfect for a wheeling truck, less mechanical devices in the mud. Also a good idea for a tow rig. Mechanical e-brakes were never meant to hold the truck plus the trailer. Put it on the front brakes and lock all 4 wheels. I originally paid over $250 for this. $100 takes it.

http://www.mico.com/

http://www.itelco-usa.com/jon/leverlock1.jpg

http://www.itelco-usa.com/jon/leverlock2.jpg