What size of string do I need to buy for my string trimmer?

This varies greatly. You either need to bring in your old string or know what brand and model you have. If you don't know, we can make a guess. If we are right, you won't have to come back. If you have an electric trimmer, it's probably .064 and if you have a gas trimmer it's most likely .080.

Check your state and local codes before starting any project. Follow all safety precautions. Information in this document has been furnished by the North American Retail Hardware Association (NRHA) and associated contributors. Every effort has been made to ensure accuracy and safety. Neither NRHA, any contributor nor the retailer can be held responsible for damages or injuries resulting from the use of the information in this document.