Multipurpose, semipneumatic tire, SemiPneumatic tires are lowcost and made out of solid rubber, so you will not have to deal with flat tires again, These tires have a hollow airpocket on the inside, but they do not need to be filled with air, nor do they need a tube, This is a great, lowcost replacement tire, 12 x 1, 75 SemiPneumatic Tire with Ribbed Tread Steel Rim, 1, 50 centered hub, 12 ball bearing, SKU: MTNI026