A simpler version of the valve lifting capital is the mechanical capital, which is either provided with a part holding a insert, which is why it is often said to be a insert holder, or it is also a joint in itself, in which case there is no separate insert. The hydraulic valve lifter, also known as hydraulic capital, is responsible for the harmonious fit between the camshaft and the valve. These capitals are constructed so that the inner middle portion is of variable length, thus serving the desired fit. For both new and used / worn engines, a built-in calibrated non-return valve ensures the correct valve clearance.