ES M-530 Direct Voltage Adaptor is an analog test meter with all the usual multimeter functions, in addition to its Peak Voltage measurement capability for troubleshooting ADI and Battery CD ignition systems. Includes manual with testing sequences for 3, 4 and 6 cylinder outboard and Mercruiser engines. Works perfectly; this is a great tool for a Marine Mechanic or a DIY guy; originally cost me over $300, I'm retired now and don't use it anymore.