Dual Wheels Upgrade Kit for Seamax Deluxe Launching Wheels and Easy Load Launching Wheels Give a 4-Wheels systemoption to your Deluxe Launching Wheels and Easy Load Launching Wheels. Suggested for large boat with wider transom. Provide better support onsoft terrain andsandy beach. Package includes: 2x 12 inch Pneumatic tire, 2 x dual wheel bearing. Note: this upgrade kit requiresan existing full set of Seamax Deluxe launching wheels or Easy Load launching wheels.