Fuse Tuning?! This is a trial set for high-efficiency fuse tuning. Fuse tuning...? Really? This is a single trial item to see if you notice a change in sound, especially with your navigation system. If you like it, consider getting one for your car! These are high-quality fuses made by a domestic OEM manufacturer, with improved conductivity, electrical performance, static electricity reduction, and special processing. *To counter imitations and low-quality products, some products undergo special processing to further enhance performance. This may appear as stains or discoloration, but it's due to the processing agent and does not affect performance. This is a processing technology that copy products & copy product-focused vendors cannot replicate. This is a trial item. I've listed it because the effect of replacing it is easy to notice with a navigation system. If you like it, please consider the set product (lol). Users of Carrozzeria, Panasonic, and Kenwood navigation systems have tested it. Many have confirmed improvements in sound quality and sound pressure. Some have even lowered their usual volume because the sound became louder (lol). Please check your navigation system's manual and specify whether you need a low-profile fuse or a mini fuse, and the amperage (10A or 15A). This is a trial item, so it includes one fuse and shipping. I will also start selling a 6-piece set of "Everyone's Tuning Fuses" separately. Please try them if you are interested. Please understand that this is a DIY product made on weekends before purchasing. We will ship them sequentially after confirming payment. Thank you very much! We have received many reports of imitations and counterfeit products from repeat customers. Please be careful and check the product descriptions and reviews. #antistaticsystem's static electricity removal tuning parts are here.