Hello eamorgan18,
Welcome to Community! I would be happy to assist you with adding inventory items to your QuickBooks Online account.
To successfully enter your inventory without error, please be sure there are no special characters in the Name* field. I recommend entering 'Elbow' instead. Then enter '3/8 Elbow', in the Description field. This will allow you to save your product.
Please don't hesitate to submit a suggestion to our Development Team, if you would like to see other options.
If you have any other questions, feel free to reach out. We would be glad to help!