1、APPLICABLE MODEL: Used for 2 stroke 15 HP ignition coil, consisting of primary coil, secondary coil, and iron core. 2、USE INSTRUCTIONS: When using, first charge the primary coil and self induce a voltage of 200‑300V in the primary coil; Then, a high voltage of 18‑20kV is generated through mutual inductance with the secondary coil. The amount of voltage generated depends on the turn ratio of the two coils, and finally, high voltage electricity is transmitted to the sparking plug for ignition. 3、RUBBER AND METAL MATERIAL: Made of premium rubber and metal materials, rust proof, anti corrosion, and durable for long term use. 4、STABLE AND RELIABLE: Our marine ignition coil offers superior performance, durability, and reliability for uninterrupted boating. 5、IDEAL REPLACEMENT: Wonderful replacement for the old and damaged parts, fine workmanship, attention to details, helps you improve the working efficiency!