The downrigger corner mounting base is equipped with four 25mm mounting brackets and fits all rigging marks. The product is made of UV-protected PE plastic, so you can easily make mounting holes for it. All edges are rounded, making it very "line friendly". The edge around the corner of the inside of the boat is rounded, so the product interferes with the interior of the boat as little as possible. Unlike the product images, the product comes standard with plastic mounting struts that do not damage the railings. If you have a really sturdy rigging that uses more than 7kg of balls, we recommend using the optional aluminum struts.