Firestone Brand Passenger Tire Inner Tube with Tr13 Rubber Valve ER12 ER13 Fits 12" 13" High quality Firestone ER12/13 inner tube with TR13 valve stem. FITS 12" SIZES 135R12 145R12 155R12 155/80R12 165/7012 145/80-12 155/80-12 550R12 560-12 600-12 FITS 13" SIZES 145R13 155R13 165/70R13 18560/13 145/80R13 155/80R13 165/65R13 185/60R13 560R13 590-13 500-12 600-12 5-12 7-12