pin connecting the attachment to the trimmer

You'd need to contact Troy-Bilt for parts. I don't recall it being sold as a repair part from the couple of times I was on their site, but they may have something. I've owned a Troy-Bilt weed eater for over a year with this and 4 other attachments. Not one of the pins has failed with rigorous use. I change between attachmetns frequently with no issues. Be sure when you install or remove an attachment that you manually depress the connecting pin. It's not designed to be installed or removed without doing this.

Hello. For assistance with that repair, please contact a local service center. You can find the nearest location by visiting our website www.troybilt.com. Thank you for your question.