The DEROYAL RT Hit Kit 77-400380 is a disposable pressure transducer kit used for right heart catheterization procedures. It includes a transducer, stopcocks, and tubing. The transducer is a disposable pressure sensor that converts pressure changes in the blood into electrical signals. The stopcocks are used to control the flow of blood through the tubing. The tubing connects the transducer to the catheter that is inserted into the heart.