The AB4 amplifier offers the same performance as the AB1A, in a reduced package. The AB4 operates off of 12Vdc supply input and can drive up to 4 HR motor elements total, either 1 x 4 element HR motor, or multiple HR motors totaling 4 elements. The AB4 is the smallest standard motor amplifier and is provided with a 26-pin rear connector (26 pin, two row header). This connector provides access to all functionality (motor, power inputs, limits, and I/O functions), making it easy to integrate. Additional motor and power inputs are available with standard connections on the front.