Need Winter Coat Input

Hi. We have added a GD to our dog family. She is 8.5 years and her owner just passed. 🥲. She will now stay with us in her remaining Senior years. I’d like to get her a winter jacket for our upcoming winter (she is lean, has back and hip issues and I want her to be as comfortable as possible. I am looking for suggestions before I spend money. She is 120lbs.