This is a muffler earth, known for improving fuel efficiency and increasing torque. With gasoline prices remaining high, it's recommended for those who want to improve fuel economy, even a little, whether for driving, leisure, visiting family, commuting, or everyday shopping! Sold as a set of 4. Total length: Approximately 25 cm (Please allow for a few millimeters of error) Terminal size: 8mm (Suitable for M8 bolts) Muffler earth is easy to install and popular as a simple tuning method that can improve fuel efficiency and increase torque. You can also install it on the muffler side using metal bands for hoses, etc., so it fits various vehicle types. (Bands are not included, so you will need to prepare bands separately for installation using bands) ⚠ Although it can be installed on various vehicle types, 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 install it so that the metal part and the terminal are in contact.