Solid Centre High Quality Suitable for industrial 2 Ball bearing to each hub Pair of 3.50-4 250x75 wheels, Plus 2 split pins Offset design with non-slip drainage grooves improve wet drainage performance. Improve tire slip resistance in wet weather. Triangular block pattern provides excellent tire grips. 4 Ply tread, high-quality rubber 16mm bore Puncture proof Bearings: High-quality bearings attached to both sides, which ensures heavy duty capacity and durability. Puncture Proof: Durable Tyre without air - resistant to nails, shards and debris. Bore: The 16mm bore is made of high- quality steels, which has high hardness and high toughness. Tread Pattern: Difference tire patterns, anti-skid, wear-resistant.