Save money Perfect size Dirt Rocket tube Straight valve stem Affordable 12-1/2″ x 2.50/2.75 scooter tube typically used on electric scooters and dirt bikes Compatible with the Razor MX350, MX400, and X-Treme X-560 as well as many other models of scooters and dirt bikes. 12-1/2″ x 2.50/2.75 scooter tube typically used on electric scooters and dirt bikes. Compatible with the Razor MX350, MX400, and X-Treme X-560 as well as many other models of scooters and dirt bikes.