Stainless Steel Poppets and Springs This ball lock post are made of green SS 304 for proper sanitation and unmatched durability. Standard thread size,Ball lock posts are with quality o-ring to prevent leaks on gas and liquid connection end,make your keg application easier than ever The ball lock post is for both gas and liquid posts.Purchase these keg posts to replace worn out posts that no longer seal properly. These ball lock posts work great with American standard Cornelius, Corny keg, Beer Growler. Standard threads. BUT NOT compatible with Firestone, Hoover, and Spartanburg kegs