The Caterpillar 390D Excavator 1/100 scale measures 4" long from the end of the body to the front of the track. When fully extended, the arm and bucket are 6.5" long. From track to track it measures 3.5" wide. The tracks are are made of rubber and can roll. 

Construction is made of diecast metal and plastic parts. The arm and bucket is entirely made of metal and the main body seems to be a mix of metal and plastic parts. 

This is definitely not a toy. It is quite heavy, so it could (as the real thing) do some serious damaged if used irresponsibly. Although sturdy and heavy for a model, it is fragile when compared to a toy. The cab and other details are tiny and fragile, so this won't last long if taken to sand box or to the back yard for a spin. 

The model comes in a window box and it measures 7.5" x 5" x 5"

The Cat® 390D/390D L Hydraulic Excavator has excellent control, high stick and bucket forces, impressive lift capacity, simplified service and a comfortable operator station to increase your productivity and lower operating costs.