Greenworks 40V 20 in Hedge Power Head, Tool OnlyGreenworks 40V 20 in Hedge Power Head, Tool Only. This is a replacement power head only for a 40V cordless pole hedge trimmer. It is designed to replace the head on model PH40B210 and PSPH40B210. The trimmer features a 20-inch blade with 5/8-inch cutting capacity for.