D series gearboxes are helical gear reducers with monoblock body in the quality of known YILMAZ REDUKTOR. D series gearboxes provide ease of assembly and compactness for many application areas due to their hollow shaft. These models are produced with flange, body connection, hollow shaft suspension connection or a combination of these. Hollow shaft gearboxes are designed in a modular system, as in worm screw models. Output shafts and output flanges can be added to the standard product later. There are connection holes that allow connection from both sides of the body. Flexibility has also been introduced in the motor connections of hollow shaft gearboxes. IEC B5 or B14, standard coupled or non-motorized shaft input models are available. Changes are minimized in combinations with other endless and monoblock models. It replaces worm screw reducers in application areas where high strength and efficiency come to the fore, and provides great advantages in terms of radial loads.