Revell Engineers Advent Calendar Hydraulic excavator model kitThis excavator with hydraulically controlled arm is assembled from 130 parts. Day by day, a small assembly group is created by simply plugging them together. Finally, fill the hoses with water and the hydraulic excavator can begin its work: the excavator arm and bucket can be moved in three different directions. With mechanical chain drive and swivelling excavator body. With the hydraulic excavator from Revell Engineers, children aged 8 to 12 can