This is an excavator arm that can be used to DIY excavator. Fitted with three motors. Three joints can be active, you need to supply it with 3-8v power to make it work, it is responsive and accurate. It looks cool but the operation is very simple. Hope you will like it. Here is a DIY work that use with this excavator arm, there are also some other products that you can buy in our website a excavator robot chassis.