Swimming Pool LED Light Transformer -LDRX120 - 120VA

"The Ledrex Power Supply unit is designed to supply 12VAC for pool lights."
means that the transformer/power supply converts the normal mains voltage (typically 240VAC in Australia) down to 12 volts AC (12VAC), which is the standard low-voltage supply used by many swimming pool lights.
Key specifications typically associated with a pool light transformer include:
Input Voltage: 240VAC, 50Hz
Output Voltage: 12VAC
Purpose: Supplying low-voltage underwater pool and spa lights
Electrical Isolation: Provides separation between mains voltage and the pool light circuit for safety
Installation: Must be installed in accordance with Australian Standards and local electrical regulations
Load Rating: Determined by the transformer model (for example, a 30VA transformer can supply up to 30 watts of lighting load)
For the LDRX120 Swimming Pool Transformer, the "120" generally indicates a 120VA (approximately 120-watt) capacity. This would typically suit:
4 x  20W–30W pool light, or
Multiple LED pool lights provided their combined load does not exceed the transformer's rating.
The power supplies are manufactured to Australian standards with seperate secondary windings per light.
The Ledrex range of pool light power supplies is designed to provide a safe and reliable 12VAC supply for LED swimming pool lighting applications.
Models Available
Model
Maximum Number of LED Lights
LDRX30
1 x LED Pool Light
LDRX60
2 x LED Pool Lights
LDRX90
3 x LED Pool Lights
LDRX120
4 x LED Pool Lights
Key Features
240VAC input, 12VAC output.
Designed specifically for LED swimming pool lighting systems.
Manufactured to applicable Australian Standards.
Separate isolated secondary winding for each pool light connection.
Suitable for new installations requiring individual isolation of underwater lights.
Spare 10A Power Outlet 
Robust construction for reliable long-term operation.
This design ensures improved safety, fault isolation, and simplified installation of multiple LED pool lights.