The unique, wedge-shaped PP-1 slides into a hydraulic disc brake caliper to pre-set the piston when replacing pads, aligning pads, and performing other service procedures. Makes hydraulic disc brake maintenance and repair faster and easier. The Park Tool PP-1 slides between the brake pads inside a caliper allowing the user to spread the pads and compress the pistons when servicing pads or wheels. The PP-1 expands the gap between the pads, making it easy to insert the disc between the pads when re-installing a caliper or wheel. "Sure Grip" dual density handle provides a positive grip.