Tamiya Mini 4WD Large Diameter Slick Tires Fluorescent Yellow - Not for Sale - Set of 2 Thank you for viewing. These were participation prizes from Mini 4WD competitions held around 2006-2007. They have been stored in a dark place, but there is some discoloration. I believe the hardness is unchanged from then. There is no stickiness due to hydrolysis. Please refrain from purchasing if you are concerned as these are old items. Thank you.