The Yuasa 6N4C-1B conventional style battery is tiny and was one of the first 6 volt batteries used in motorcycles to power the head lamp. Most all the 6 volt conventional batteries will have very similar part numbers indicating only the type of connector has changed or where the vent tube is located. In some cases, depending on the application, this is very import and will mean you must make sure you match the exact number. In other situations you can substitute a similar part number where the base SKU is the same. i.e. 6N4-2A is the base SKU and 6N4-2A-3 has different connectors.