I bought it, but I ended up not using it. I've attached it to a car once, so it's a used item. Quoting from Amazon: Ilector Pipe Car Roof Carrier Bar Spacia Ilector Pipe Attachment Van Compatible Inner Hexagon Aluminum for Mounting DIY Production (Set of 4 & Metal Joint) ・Application: By combining the attachment and metal joint, you can securely attach the Ilector pipe to the car body. You can store equipment for fishing, camping, car camping, surfing, and snowboarding. ・【Product Specifications】The aluminum pipe size is 27.5mm in diameter and 32mm in length, and the hole diameter is 6.5mm. The material is aluminum, and the bolt diameter is 4.5mm. ・It's an item with high precision and excellent texture, and it was almost easy to install using the included tools. It's perfect for customizing the interior of your car.