Deluxe Universal Masthead Mount by Davis Instruments®. Extend your Windex 10.Sport or Windex 15 vane away from masthead obstructions. The 13" (33 cm) arm comes with hardware to allow for side or top mounting and offset angles up to 20 degrees. Mount on the back of the mast for easier viewing from the cockpit. Can be used with the Windex Light. Length 13 inches (33 cm). Weight 3.2 oz (90 g). This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers in mind, this product by Davis Instruments will last a lifetime. It will meet your needs and deliver great quality at an affordable cost.