COMPATIBLE WITH - Upgrade Inflatable Valve Adapter compatible with Thermacell Butane Cartridge APPLICABLE SCENARIO - With this adapter, you can easily refill your cartridge.You have to remove check valve on the cartridge for the adapter to work!The smaller O-ring is located on the inside of the adapter, while the larger O-ring is located on the outside.Thus sealing the adapter and valve core, achieving the function of refilling the ink cartridge. High quality materials -100% brand new and of high quality. Made of high-quality materials, durable and convenient to use. High security, stable connection, and strong sealing PACKAGE INCLUDED- Includes adapter and 2 extra orings NOTE:Please verify before purchasing that it is the part you need. Upgrade Inflatable Valve Adapter compatible with Thermacell Butane Cartridge(Includes adapter and 2 extra orings)