1. This pack of 4 snap-in valve stems is easy and convenient to install. Simply pull them through (if there is tension, the diameter will reduce and then re-expand for a tight seal).2. They are designed for tubeless 0.453inch (11.5mm) diameter rim holes and are the industry standard for passenger cars and light trucks.3. Constructed from a standard brass core and ozone resistant EPDM rubber, these stems are leak-proof , up to 65 PSI (448kpa). 4. Material: rubber + copper (Durable steel construction，Molded rubber coating protects rims and wheels)5. Installation method: snap-on6. Features: high temperature resistance, aging resistance7. Package Includes: Car valve TR418 x 4 ，Tire valve core x 4, Valve core wrench x 16. Made for installation or removal of snap-in type tubeless tire valves8. Note: Be sure to check if the valve should be installed before use.

http://olla.gr/snap-in-short-black-rubber-valve-stem-tr418-4-pack-with-valve-core-wrench-for-tubeless-0.453-inch-11.5mm-rim-holes-on-standard-vehicle-tires/