General description A necessary replacement trimmer part for Echo Speed Feed 400 models including SRM-225, SRM-230, SRM-210, and Echo Weed Eater models PAS210, PAS211, and PAS225. This trimmer head is designed for easy installation and efficient performance. Technical specifications Max Cutterhead RPM: 10,000 Cutterhead Diameter: 3-3/4 inches Thread Size: M10mm x 1.25mm Thread Direction: Left Hand Package contents 1 x Cutting head