Mold for the production of prefabricated reductiong ring type Konus DN900 and maximum height 450mm. Coat of the mold is made of a steel structure made of S-355JR sheet, equipped with manual locks for locking the bottom sleepers and transport holes. The mold core for the production of a prefabricated product equipped with sleeves for fixing the central mechanically interlocked vibrator. Equipped with a system for mounting drawers (inserts) for direct vibration, for example, of manhole steps.