Hello, which cork size should I purchase with these? Thank you

With a 21.5 mm bar‑top neck finish, you will need a 22.5 mm bar‑top closure to achieve a proper, tight seal. We recommend testing to your end use prior to placing a large order to confirm fit and performance. For more information, or if you have additional questions, please reach out to our Customer Support team at online@tricorbraun.com.