This is a set of two 【Universal Reinforced Resin Baffle Boards】 used when replacing the original speakers with aftermarket ones. ■Dimensions (actual measurements) Inner diameter: 146.5mm Outer diameter: 170.5mm Thickness: 17.5mm Hole center distance: 157.5mm Suitable for general 6.5-inch models from overseas manufacturers. 17cm speakers from domestic manufacturers can also be installed, but there will be gaps. If your vehicle is compatible, the following product is recommended. ★Product Title: Carrozzeria TS-V173S Compatible Aluminum 6.5-inch Baffle Board for Speakers ※Please confirm compatibility with your vehicle and the dimensions of the product you are installing. ※This product may have minor scratches or scuffs that do not affect its use. Please refrain from purchasing if you are overly concerned about this. Unlike MDF or wood, it is less prone to corrosion and can maintain its performance almost permanently. It has high plasticity, and even if the hole positions or number of holes do not match, it can be easily customized with a drill. It can be used as a base for inner baffles and outer baffles. For those who want to pursue sound quality, we also offer aluminum baffle boards and 3mm thick aluminum spacers. If you are interested, please search for the following product titles: ★Product Title: Aluminum Universal Inner Baffle Board Overseas 6.5 inch Domestic 17cm Speaker Compatible ★Product Title: 3mm Thick Aluminum Wide Spacer for 6.5-inch Speaker Baffle Board ■Important Notes Due to the nature of the product being a processed item, refunds will not be provided for any reason. As this is an imported product, please refrain from purchasing if you are overly concerned about perfection.