YunSCM 4 Pack 20'' Fat Bike Tyre Tube 20 x 3.50/4.0 Heavy Duty InnerTubes AV32mm Schrader Valve 20" Bicycle Tubes Compatible with 20x3.5 20x3.6 20x3.7 20x3.8 20x3.9 20x4.0 MTB

Size: 32mm (Regular valve). Fits all 20" x 3.5/4.0 tire tubes, compatible with 20x3.5/4.0 Road bike /Mountain bike Tire bicycle tire tubes. High Quality: The bike tube is made from premium butyl rubber.It has the advantages of good sealing performance, ozone resistance, aging resistance, shock absorption, electrical insulation. Comfortable and Safe: After replacing the butyl rubber tube, it absorbs the impact on the uneven road surface, making riding more comfortable and safe. Easy Installation: Installation is quick and easy. Please follow inflation guide when airing a tire from a complete flat. Save time and effort, replace the old tube in a few minutes Installation Precautions: Please check the side of your tire for the tire size your bike uses. Important Note: When changing a bicycle inner tube, be sure to add a little air before installing it. This gives it form so it doesn't get twisted or bunch up which may cause a pinch flat. Inspect for an even bead of the tire to the rim on both sides.