The only difference between NP7-12 and NP7-12L is the width of the push-on tab connector, the NP7-12L has 6.35mm wide connectors which are generally used for UPS Backup systems, it is important to use the "L version" with wider terminals for UPS backups to ensure a tight fit which will prevent any loose connection issues

The NP7-12 has 4.75mm wide connectors which are generally used within alarm systems, all other specifications such as length, width and height are the same including the performance.

You will notice a price difference of 1-2 pounds between the two versions, this is due to Yuasa selling the wider "L version" at a slightly higher price