Shop Wiseline Tools for Dewalt String Trimmer's. Cut through overgrowth instantly with our lightweight, ergonomic, and robust Dewalt 20V MAX* and FLEXVOLT® 60V MAX* string trimmers. Dewalt's 60V MAX* string trimmers easily go the thickest grass with the power of FLEXVOLT. Plus, when you use FLEXVOLT batteries in your 20V MAX* string trimmer you can get up to 8x the runtime.