This is a muffler earth product, known for improving fuel efficiency and increasing torque. With gasoline prices remaining high, it's recommended for those who want to improve fuel economy, whether for driving, leisure trips, visiting family, or daily commutes and shopping! Sold as a set of 4. Total Length: Approximately 30cm and 25cm (Please allow for a few millimeters of error) Terminal Size: 8mm (Suitable for M8 bolts) Includes 2 x 30cm cables and a set of 30cm and 25cm cables, for a total of 4. Muffler earth is easy to install and popular as a simple tuning method that can improve fuel efficiency and increase torque. You can also use metal bands for hoses to attach it to the muffler side, so it can be installed on various vehicle models. (Bands are not included, so you will need to prepare bands separately if you use them for installation) ⚠ Although it can be installed on various vehicle models, please research the compatibility, required cable length, and actual installation yourself. Instructions are not included. ⚠ To maximize the effect of the muffler earth, please remove rust, dirt, and paint from the installation area and ensure that the metal part and the terminal are in contact during installation.