That's a dimmer. The installation sheet shows it powered from 12 - 24 VDC and its output connected to the LED strip. Just find a 12V PSU with an output rating greater than your LEDs need, and use it to supply the item you linked to.
So as we discussed then a 2.5A 12V PSU like a laptop one.
I was just struggling to see why all the led web sites are pushing the LED driver (transformer/psu) like the one pictured above, and all the ebay ones are pushing the laptop style psu brick. Therefore I thought the laptop style brick may not be supplying a true constant voltage or not able to handle the PWM or something like that.
Didn't want to burn out my leds prematurely, or worse still start a fire!
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