Powerslot Front Brake Rotors 350Z 03+. Power Slot's exclusive Vac-U-Slots are machined into the rotor and help evacuate gasses and dust, shed heat, and keep the brake pad surface clean. And in wet, raining conditions, our Vac-U-Slot helps push water off the braking surface for better stopping power. The Vac-U-Slot also serves as a visual wear indicator. The slot is machined to the rotorís minimum thickness where it crosses the outside edge. If you cannot see the slot along the outside edge, the rotor has worn down to its discard depth.