Hydraulic built-in valve for a valve block, comprising a sleeve that is introducible into the valve block, and a closing element, - the sleeve comprising a first end region, and the first end region being connectable to the valve block, - the sleeve comprising a second end region which is at the opposite end from the first end region, the second end region having a frontal opening in a frontal end, and - the sleeve forming, between the first end region and the second end region, a shell having an outer side and an inner side, and the shell of the sleeve having a plurality of shell apertures separated by shell partitions, and - the closing element being movably arranged in the sleeve, the closing element being movable between a first position and a second position, and, in the first position, a fluidic connection between the frontal opening and the shell apertures being opened and, in the second position, a fluidic connection between the frontal opening and the shell apertures being closed off, the shell apertures extending along the shell from the first end region to the second end region and providing an aperture height, and the closing element, starting from a sealing surface of the closing element having a first diameter, tapering, via a second diameter, to a third diameter in the center of extension of the closing element, the second diameter being smaller than the first diameter, and the third diameter being larger than the second diameter, characterized in that the shell apertures have a height-width ratio of at least 3:1, the shell apertures in the shell providing a total width of at least 75% of the shell outer circumference, preferably 80% of the shell outer circumference, the shell apertures in the shell being trapezoidally tapered in their extension from the outer side of the shell to the inner side of the shell, the width of the shell apertures on the inner side of the shell ranging from 20 to 90% of the shell apertures on the outer side of the shell. - the sleeve comprising a first end region, and the first end region being connectable to the valve block, - the sleeve comprising a second end region which is at the opposite end from the first end region, the second end region having a frontal opening in a frontal end, and - the sleeve forming, between the first end region and the second end region, a shell having an outer side and an inner side, and the shell of the sleeve having a plurality of shell apertures separated by shell partitions, and - the closing element being movably arranged in the sleeve, the closing element being movable between a first position and a second position, and, in the first position, a fluidic connection between the frontal opening and the shell apertures being opened and, in the second position, a fluidic connection between the frontal opening and the shell apertures being closed off, the shell apertures extending along the shell from the first end region to the second end region and providing an aperture height, and the closing element, starting from a sealing surface of the closing element having a first diameter, tapering, via a second diameter, to a third diameter in the center of extension of the closing element, the second diameter being smaller than the first diameter, and the third diameter being larger than the second diameter, characterized in that the shell apertures have a height-width ratio of at least 3:1, the shell apertures in the shell providing a total width of at least 75% of the shell outer circumference, preferably 80% of the shell outer circumference, the shell apertures in the shell being trapezoidally tapered in their extension from the outer side of the shell to the inner side of the shell, the width of the shell apertures on the inner side of the shell ranging from 20 to 90% of the shell apertures on the outer side of the shell. the shell apertures extending along the shell from the first end region to the second end region and providing an aperture height, and the closing element, starting from a sealing surface of the closing element having a first diameter, tapering, via a second diameter, to a third diameter in the center of extension of the closing element, the second diameter being smaller than the first diameter, and the third diameter being larger than the second diameter, characterized in that the shell apertures have a height-width ratio of at least 3:1, the shell apertures in the shell providing a total width of at least 75% of the shell outer circumference, preferably 80% of the shell outer circumference, the shell apertures in the shell being trapezoidally tapered in their extension from the outer side of the shell to the inner side of the shell, the width of the shell apertures on the inner side of the shell ranging from 20 to 90% of the shell apertures on the outer side of the shell.