It's small and easy to install in your RC airplane or RC car.Tyres are made of PU sponge, hub are made of plastic, perfect replacement. SpecificationsMaterial: PU sponge Tires,Plastic HubPer Piece Weight: 16gAxle hole Diameter: 3.8mmOutside Diameter: 3" / 75mmTires/Total Thickness: 1.02" / 26mmHub Diameter: 1.36" / 34.5mmOverall Size: 3" x 1.02" / 75 x 26mm (diameter*thickness)Color: Black Tires and White Hub Package Content:2 x Tires2 x Hubs