The heavy duty inside corner dock construction piece should be used with one of the outside corners. The dock construction piece measures 8 1/4″ long by 5 inches high. This 90 degree corner has a reinforced piece on the inside of the corner piece. Manufactured out of steel and is great for your dock construction projects! 8 mounting slots, 4 on each side. Manufactured by Tie Down Engineering. Ships directly from BH-USA.