Heatsink at the Bottom of the Slime Blower

There is a black heatsink at the bottom of the Slime Blower. It is attached to the bottom tray. Does anyone have any idea on what kind of heat sink this is?

Found two modern equivalents:

For a bottom tray roughly 3 inches in measurement front to back:

Pardon Our Interruption...

For a bottom tray roughly 4 inches in measurement front to back:

Both have to be painted black obviously.

i actually went with one of these after you posted the ebay links and i love it!! thanks for finding these!!