A power tool and system for trimming and cutting vegetation are disclosed. A method of attaching a working assembly, such as blade carrier assembly, to a power tool is also disclosed. The power tool includes interchangeable cutting elements that can be readily attached and detached from a main body portion without any preliminary alignment steps. The main body portion of the power tool includes a selectively actuatable motor including a rotary output and a rotary drive element including a resiliently biased drive pin. Blade carrier assemblies are capable of being selectively and removably attached to the main body portion and each include a moveable blade portion having a drive pin slot. Upon attaching a blade carrier assembly to the main body portion and actuating the motor, the resiliently biased drive pin is rotatable to a position such that the drive pin is resiliently forced into the drive pin slot of the working piece to actuate the working assembly.