This inner tube is made of isobutylene isoprene rubber, which is better in air tightness, elastic cushioning and aging resistance than natural rubber NOT recap Heavy duty inner tube with bent valve stem TR87, max inflation is 30 PSI Inflate with manual pump only 4 10 3 50 to 4 inch inner tube works with hand carts, carts, garden cart, garden cart, lawn cart, utility cart, flat carts, lawn mowers , small tractors, wheelbarrows, yard trailers, wagon carts, rail cars, generators, snow throwers and most 410 / 350-4 wheel applications Perfect fit for 4 10 / 3 50-4 inch TIRES / WHEELS: Replacement tubes for 4 10 / 3 50-4 tires / wheels (10 inch outer diameter) also measured in 4 10 3 50-4, 410 / 350-4, 3 5-4 4, 4 1 / 3 5 4, 4 10 3 50 4, 4 10 3 50-4 , 4 10 / 3 50-4, 4 10 / 3 50-4 inches, 4 10x3 50 -4 in inches CUSTOMER SATISFACTION: Before installation, check whether the air chambers are completely sealed by immersing them in water, if there are bubbles, they are already damaged