Both RBC11 and RBC55 use the same batteries, however there is one very IMPORTANT difference which is the grey connector which is different, the connectors look similar but they are different.
If you purchase the wrong RBC battery it will not fit your UPS Backup because the plugs are not compatible with each other, therefore you must ensure you check the exact model of your UPS to ensure it will fit.
If you have ordered the wrong one you can always use your existing connectors from your old batteries and simply swap them to the new battery saving both time and money returning the items, this process normally takes less than 10 minutes to complete requiring just a screwdriver and pliers.
Click below to see which battery will fit your UPS Backup.