How It Works:

1. Magnet holds bottle above the cylinder.
2. When bleed screw is opened and the brake pedal pumps fluid into bottle, air bubbles will rise to the top of the fluid.
3. When brake pedal is released, fluid only will be drawn back into the cylinder without any air. Some of this fluid will leak past the loosened bleeder nipple temporarily acting as a seal against air re-entering the brake system.