We are selling our lightly used waterproof car top cargo carrier. This can be used with or without roof racks. It helped tremendously on vacations where we needed to have more space in the vehicle. We probably only used it 3-5 times and mostly used it to store our beach gear, stroller, etc.
Here is the original listing when we bought it so you can see the details. It is used but it great condition.
https://www.amazon.com/dp/B0042H6BA0?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_6