This tool is used for accurately measuring squish clearance. Compatible with all Zenoah /Quickdraw/ CY / RCMK RC engines. Also compatible with other engines that use a "vertical" 10mm spark plug. To get the most power from your engine the squish clearance should be set as accurate as possible without the piston hitting the top of the cylinder during operation. Use this tool to measure piston to head clearance. Comes with instructions.
