Jeff, nope!
Steenamaroo, what Alesis amp has a heatsink that big??? That chunk I'm holding is about 17" wide and the aluminum is so thick...it's heavy...I was struggling to hold it like that extended out so I could get it all in the shot.
BUT...we're getting closer...it's from an amp...an amp kit that was never assembled. My dad got it for $5 at a garage sale and gave it to me...not just heat sink, the whole kit.

it's almost all there but unfortunately missing the faceplate and cooling fan but I'm not complaining.