No Gas Leaks:The ball lock keg posts each wears a food grade standard size o-ring to prevent leakage of the connection between the ball lock and the ball lock keg posts; The Poppet valve each on the ball lock keg posts also has a standard size food grade o-rings to prevent leakage of the Poppet valve. Using the ball lock keg posts to convert a pin lock perfectly into ball lock. Solid and Durable:The Extra add tensile strength makes the spring is pretty stiff allowing for a strong seal. The posts, poppets and springs are made of stainless steel 304 for proper sanitation and unmatched durability. Standard SIZE:The ball lock keg posts have a standard 19/32inch -18 thread size. Standard keg posts are 7/8inch star on The gas inlet and 7/8inch Hex on the liquid outlet. These are both 11/16inch Hex. Make sure you put the one with the horizontal grooves on the gas inlet side. Standard Ball lock keg posts will make your installation and use easier than ever. Free O-ring:In every ball lock keg post package, we give a set of O-rings for free, so don't worry about leaking when replacing a new O-rings. Just enjoy your craft beer. Size: approx.31*22mm Color: Silver and black Material: plastic, metal Package Contents: 1 * Set of ball lock keg post Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.