This pack of 5 O-rings from FABORY is a must-have for any hydraulic setup. Measuring 3-1/2 inches inside diameter and 3-7/8 inches outside diameter, these O-rings are made from high-quality materials and have a 90 Shore A hardness rating. They are designed to fit perfectly in any hydraulic system and ensure a secure and leak-free connection. Whether you're a professional in the hydraulics industry or a DIY enthusiast, these O-rings are an essential component to have on hand. Don't let a faulty O-ring bring your system to a halt - order your pack of FABORY O-rings today!    BURNA-N (OR NITRILE) O-RINGS CREATE MULTIDIRECTIONAL SEALS BETWEEN TWO PARTS IN POWER TRANSMISSINS OR HYDRAULIC/PNEUMATIC CYLINDERS MADE IN ROUND PROFILE,THEY RESIST GREASE AND OILS,AS WELL AS MILD CHEMICALS AND WATER.