The Sol-Ark 48V Inverter/Charger product line is a product designed and sold in the USA.
The relevant product line is shown here:
Sol-Ark products hold full USA general, plus additional California specific grid connection certifications.
They are flexible and powerful hybrid (solar+battery+grid interactive) devices.
The model names (e.g. 5K, 8K, 12K, 15K) reflect the maximum solar panel capacity for each unit. The AC inverter/charger power rating for each unit is shown separately in the specifications for each product (for instance, the 15K unit, per the spec sheet, supports 15K of solar and 12K continuous battery invert/charge power.
Integration with Redflow ZBM's is simple, using the standard CANBus battery status protocol and a simple cable between the Redflow BMS and the Sol-Ark unit.