Compression Tester Not To Measure Compression Ratios

There are also tools for measuring compression. But, not for measuring engine compression ratio. Compression pressure but only just. Yes, compression tester. The tool is operated through derat plugs. Later, this measure will provide unit aka Psi pressure in the combustion chamber. So, not the compression ratio.
The use of this tool to more accurately measure leakage following the occurrence of compression. For example, in a motor before the race and after the race. After racing wear, compression will usually go down. Use this tool, it is easier to check them. For example the previous 23 Psi, dropped to 20 psi. After knowing the amount of decrease, stay longer in service or repair engines.