The RYOBI 4 Cycle Replacement Power Head is the power source that delivers power & performance without the hassle of mixing gas and oil. The replacement power head is the perfect way to step up to 4 cycle power from your current 2 cycle or to replace the older unit you currently have. This low emission engine gives you reliable power for any of the Expand-It universal attachments; all backed by a RYOBI 3 year warranty. Quickly click the attachment into place and go. Whether you are trimming around your walkway, cultivating your garden bed, or keeping your hedges manicured, the 4 Cycle Replacement Power Head is the power source to get tackle any task.