The FRO heavy-duty downhill tubes offer maximum protection for the toughest conditions you will encounter. With 4 different sizes, you can get the correct size for your needs. Matched with FRO tires, you can't get much better downhill flat protection from a conventional tire and tube combo. They are a thick motor cross style tube. 1.7mm wall thickness with 40mm valve length. Sizes-26 x 2.35, 2.7"; 24 x 2.35"; 24 x 2.6-3.0" SV only