If it's just this manufacturer, then it's better to get this model:
https://kingledlights.com/products/king-1000w-quantum-led-grow-light-3x3ft-coverage-full-spectrum-grow-lamp-for-indoor-plants-dimmable-veg-bloom-light-for-hydroponics-greenhouse-commercial-indoor-led-grow-with-326pcs-leds
Also, keep in mind that this lamp and the one you suggested have no real 1000w power!!! It's actually 150w! What they advertise as 1000w is just a marketing gimmick!
There are equally good lamps that are not more expensive from Viparspectra and Marshydro. I recommend checking out these manufacturers. 😁👌
For your box 1.2m x 1.2m, you need at least 2 of these lamps. Look for the actual power for 1.2×1.2m, which is about 300-500w of real LED lamp power.