You can dial in your advance setting and it will read RPM as well (see pictures). I just don’t use this anymore. I hooked it up to my older truck to get pictures in operation. The advance setting appears to be pretty accurate.
Vintage 300 PSI Compression Tester Dial 32881 Special Valve Core KAL/EQUIP
Vintage Kal-Lite 6/12V Timing Light Kal-Equip Co. made in Otsego Michigan USA
VTG Kal-Lite 6/12V Timing Light, Dwell /Tach, & Ignition Testers, Kal-Equip Co.
Kal Equip Inductive Timing Light #2076
