6v LED car bulbs available from LED Shop Australia in:
1156 BA15S AMBER - this version is non-polarity.
1156 BA15S WHITE - this version negative earth only.
1157 BAY15D RED brake light bulb (Double Acting brake/tail function) - non-polarity version.
BA9S WHITE - non-polarity version.
(Non-polarity - able to operate on negative and positive earthed systems.)