This is a 4.10X3.50-6 (13X4″) foam filled knobby tire, Fits most. Foam filled tires are Primo pneumatic tires filled with urethane foam, so they are a tire inside of a tire. These are made for 2 piece wheels only, they are flat free. The bead to bead width is 3.25″. Maximum rider weight is 250 lbs. Sold as each.