NO FLATS!!! Ground Support Products offers a range of 'soft ride' solid tire and wheel assemblies. Made of 100% natural rubber with a 3-stage design, the free rolling tread design and rib tread prevents cupping and vibration problems. Available sizes: 4.00x8, 5.00x8 and 6.00x9. For use on dollies, baggage carts, tugs, and misc. gse carts