Overview Reviews Product Description 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. Lisle Tools Catalog Product Videos Custom Field Harmonization code HTS #9031809080 Manufacturing country US Product Reviews Write a Review Write a Review × Lisle Inline Spark Tester 20610 Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Review Subject * Comments *