Inline Spark Tester WATER FILTER 2101909A cross reference listing means

2101909A cross reference listing means that this item should be a suitable replacement for the part numbers listed

Enhanced detergency and dispercency to prevent and control sludge

5" length extension for better access to hard-to-reach fasteners

Strong resistance to oxidation and thermal degradation especially during high temperature operation

Inline Spark Tester WATER FILTER 2101909A cross reference listing meansGives a Visual Check of the Ignition System. Quickly diagnose problems with all ignition systems. Connect the tool between the spark plug and the plug wire. The tool is double ended to offer a straight boot and a 90 boot on one tool. With the engine running, the tool flashes a mirror image of ignition spark.