Nice heatsink in titanium color.
This one is designed for motors that are placed like on belt-drive chassis.
If you buy a cheaper one with the heatsinks on the other direction, your motor will not be so cool as with this one, the air gets through the vents and cools a lot better.
There is also a hole in it, you can place a fan in that hole, so it cools even better.
It's maybe a bit expensive, but this are parts you just buy once, so you better can choose for the right one for your chassis.