Q-Tubes Thorn Resistant 27. 5" Inner Tube These Thorn Resistant tubes are made of butyl rubber and measure 4mm thick in the tread area and 2mm thick in the rim area for durability. They are available with a schrader or presta valve and have removable valve cores. Keep the thorns out and the air in. Ride on. Features Size 27. 5 x 2. 0-2. 25"4mm thick in the tread area and 2mm in the rim area32-40mm valve Presta or Schrader valve options Removable valve cores | Quality | Teravail Thorn Resistant 27. 5" Inner Tube Presta, 2. 0"-2. 25" | Rubber