Echo PET4000EC Spark Tester Genuine OEM Echo Part Replaces: 99051130023, 89780079930, 89780079931 Oppama PET-4000 Adjustable Gap Inline Spark Tester Not only checks for spark, but has a fine adjustment to test for spark at the correct firing voltages. Each 1mm graduation on the adjustable gap represents approximately 2,000 volts in firing voltage. Can check for spark between 2KV and 25KV with ease. Checks spark while running, or not running.