This 4WD Utility Mobile Platform – Dorado is easy to build and cheap, it is the best platform for you to build your first mobile application. The Dorado platform consists of Dorado skeleton that made of Acrylic board, gear motor, wheel etc. Besides, there are also 4 circular grid board made by Acrylic, with a laser or infrared emitter and sensor, it would be possible to measure the speed of the platform.     There are also 2 kinds of motors for your different requirements, you can select the 50 r/min and 125 r/min version in your order, the default would be the 50 r/min. Note that the Dorado Skeleton board is black acrylic, remove the yellow protect paper before your installing.