Trying to identify a connector
It is a semi-proprietary connector. It is almost certainly not available as a commodity item. There are MANY similar-looking connectors. Some of them may even mate with that connector. Beware to use something that is not reversable (inverting the polarity which will toast your "car equipment".) Some possible solutions include...


If you really want the exact connector, you will have to buy something that includes that connector.  Or you could modify your "car equipment" to have a more standard, commodity connector.
You could use your single cord with the "special" connector and make an adapter cable to use a more standard, commodity connector.
You could modify your "car equipment" by replacing the oddball connector with a standard, commodity connector.