Review on BPA-RACING Motorcycle Chain Slack Adjuster Tool - Advanced Chain Tensioning Tool for Effortless, Rapid & Accurate Chain Slack Adjustment - Slack Setting Tool (Blue) by Robert Dabney

The tool only seems to work if your chain is too loose or too tight and not suitable for the intermediate position. The chain sag on my 08 R6 is 30-45mm. My chain was 40mm long when I calibrated it. I tried my buddy's chain and it was 36mm long. I used the tool and the tool was in the same place. Now my chain is 43mm long and the tool still shows the same spot as last time. I think this only works if your chain sag is less than 10mm or more🤷‍♂️.