[Widely used for REAR WHEEL]-Attention please: Only rear wheels can be used. If you are looking for inner tubes for front wheel, please check at our stores we have 8.5 inch 50/75-6.1 tubes with straight valve that can be used for front wheel. [THICKENED & PUNCTURE-RESISTANT] - Our inner tyre adopts the thickened design, 4pcs 8.5 inch thickened inner tubes can be used on the rear wheels. Our tires are 1.9mm thick, which are stronger than the tires and have better puncture resistance. It can be use for a long time. [HIGH-QUALITY MATERIAL] - Electric scooter inner tube is made of high quality butyl rubber material, which has good thermal stability and air tightness, and is also environmentally friendly, non-toxic and harmless. [EXTENDED VALVE]- in order to make it easier to inflate the inner tube, we have extended the valve of the inner tube. The extended valve can inflate the inner tube more efficiently. At the same time, the curved mouth valve nozzle plays a better role in protecting the inner tube, so don't worry the inner tube is easy to puncture. [EASY INSTALLATION] - To make changing the inner tire more convenient, we have equipped 4pcs Colour:black Material:rubber Package Contents: 4 x inner tubes 4 x wrenches