Sure, why wouldn't it be? Are you using the 14 gauge wire and what length are you needing? If running crazy long lengths double the 4 conductors together which will give you an effective 11 gauge cable.
Here is a URL for that item on JBL's website. Download the Manual. Or call Customer Service for help.
https://www.jbl.com/bluetooth-speakers/JBL+Flip+4.html
Verizon wireless sell this item. Take it and all accessories to them and ask for help? Good luck!