The Park Tool DAG is something almost every bike mechanic raves about. I finally got my hands on the updated DAG-3 tool released earlier this year and put it to good use on my bikes to ensure crisp and accurate gear shifting.

Park Tool DAG-3 Derailleur Hanger Alignment Gauge (Amazon US): https://amzn.to/3gFMSyb
Park Tool DAG-2.2 Derailleur Hanger Alignment Gauge (Amazon US): https://amzn.to/2WtIWd3
Park Tool Official DAG3 Info: https://bit.ly/3yxqhdv