The silicone catheter is mainly composed of the main body and the lumen head, which can be divided into single lumen without balloon, two lumen with balloon and three lumen with balloon. They are divided into several sizes according to different pipe diameters. Two-cavity type specification Fr6-Fr24; Three-chamber specifications Fr16-Fr24. Structural features: Two - and three-cavity catheters have a balloon about 2cm from the head of the catheter, which can accommodate liquid or gas, and a cavity of the catheter is connected with the balloon, and there is a piston at the end. After a syringe is used to inject liquid or gas through the piston, the balloon will immediately expand. When the syringe is removed, the piston automatically closes, which prevents the gas or liquid in the balloon from escaping the body. At this time, the enlarged balloon is fixed in the bladder to preserve the catheter, and the other cavity of the double cavity is the drainage cavity, which can be connected with the drainage tube and urine bag. When pulling out the double-chamber balloon catheter, use a syringe to drain the gas or liquid in the balloon, and then gently pull out the catheter.