Ideal for coffee enthusiasts and professional needing replacement parts to restores original grade sealing in BES840XL, Infuser BES840, or BES880BSS machines Premium food grade silicone sealing rings for ensures durability ( up to 3000+ cycles) and leak proof in coffee machines like 878, 870, and 880 models Precisions engineered 54mm silicone rings features smooth surfaces for effortless cleaning and maintains optimal pressure during espresso extraction, outperforming standard rubber seals Perfectly seals portafilters during daily espresso brewing for home, offices, or cafes, leakage while enhancing consistency in coffee shots This 2 pack silicone seal set extends coffee machine lifespans by replacing worn out rings that cause pressure loss, ensuring compatibility with 54mm group heads across 20+ models