Ø Cover Mm 310 - Ø Hole Mm 28, 5 - For Kegs Kg 25 The Membrane, Like The Lid, Is An Accessory Or, Which Is Always Recommended, But If You Use Very Hard Grease, It Becomes Indispensable, Because It: • Compresses The Fat Avoiding The Formation Of Air Inside The Drum. • Collects All The Fat Of The Stem Minimizing The Waste Of The Same.