Air-Liner GRAVEL is an insert for tubeless-ready gravel tires. Re-usable and very easy to install – as easy as mounting an inner tube on your tire – Air-Liner GRAVEL it is compatible with tubeless-ready tires only and with 3-way valves (in the packaging, 5-way valves are provided for ultimate airflow). The insert can be used with sealant – preferably without ammonia