The ECHOmatic Pro is designed for more demanding tasks over the standard ECHOmatic head. With a maximum line diamter of .130 in., tough grass and weeds are no match for this unit. This easy to load, bump-to-advance system reduces downtime so you get more done in less time. The 2 piece head construction with a partitioned spool reduce line tangles for even more efficiency. For use with ECHO SRM model trimmers only.