I've got one of those on My bedtime reading light, but I stripped the guts from the Box to fit inside my light. Bought it on Amazon for ~5 bucks, free shipping.
It has no Heatsink.
It works well on my Sub 0.1 amp LED reading light. I feel the dimmer light allows me to fall asleep faster.
When used to control a 1 amp 92mm 12v muffin fan, the muffin fan whined at slower speeds.
I got a 25khz 10a pwm controller that lowers the fan speed without whining, but curiously when powering some CREE LED's, the LED's whine when dimmed.
http://www.amazon.com/Converter-12V-36V-Adjuster-Controller-Driver/dp/B008BGLMYS/ref=pd_sim_sbs_e_4?...They are available for less if one searches. I first bought this model from Ebay, but it came horrendously packaged and was missing the parts for attaching the wires. They sent me another, and now I have 3.