STIHL AutoCut C4-2 is a semi-automatic, dual line cutting head for trimmers. It is suitable for lawn trimming and mowing large areas of grass and weeds. The cutting head is easy to load by inserting the line into the eyelets and twisting the knob. It is important to follow all safety precautions in the instruction manual to avoid serious or fatal injury. The cutting head should not be operated at more than 10,000 rpm.