COMPATIBILITY: 2.75/3.00-21 Inner Tube Fits Motorcycle with 21inch Tires, great 80/100-21 Replacement Inner Tube With TR4 Straight Valve Stem SAFETY FIRST: We designed this inner tube to be explosion proof. When and if punctured, it immediately creates an airtight seal to prevent damage, destruction and injury to the rider GREAT PERFORMANCE: The inner tubes are double thick, more durable. Improved version thicker rubber tubes which are tear-resistant, scratch-resistant and durable in use EASY TO INSTALL: The replacement inner tire is extremely convenient and simple to install and detach. Please check the position of the valve, and make sure you install them in the right direction Specification: Feature: Inflatable Inner tube is made of isobutylene isoprene rubber, better than natural rubber in air tightness, elastic damping and aging resistance. Suitable for off-road Chinese dirt bikes, pit bikes, trail bikes and other motorcycles. colour: black Material: rubber Package Contents: 1 x Inner Tube Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.