This MOTO-STOP is designed to fit Mercury 2 and 4 stroke motors 150-250 hp that incorporates the use of two trim rods with an approximate trim rod distance of (4 7/8) from center to center and a trim rod diameter of (5/8th of an inch). Will NOT fit Mercury 150 motors 2017 and newer - they do NOT have trim rods, which are required for installation of this product. IMPORTANT to check measurements for a sure fit. MOTO-STOP bodies are made of 6061 aluminum with bushings and pads of 95 durometer urethane.The assembly hardware is all stainless steel. These materials make for a very strong, durable and quality product. To use simply raise the motor, slide the Moto-Stop over the trim rods and lower the motor and snap on clips. Units come as shown here with a heavy duty canvas bag to prevent soil transfer and a pair of steering rod clips. This is another product we fully guarantee and are proud to say is made in our cnc machine shop in Northern California. Check our other items for tools and accessories.