Answer
String Trimmer (Also Called A Strimmer or Weed Eater) (Ballas got the idea for the device after using an automatic car wash and used a tin can and fishing line connected to an edge trimmer to test out his idea which he later refined. His invention was rejected by many toolmakers and Ballas was forced to produce the device himself. The invention was a hit and by 1977 it had gone on to produce sales of over $80 million)