Heatsink Top:
With the fan removed we find a 4mm space between the base of it and the tips of the fins. Both fins angle inwards to where the clip is located, and the base rises up in a triangular fashion. It is hard to say what this open space will add to the overall thermal effectiveness of the JVC258A, but since this area is directly under the fan motor there is little likelyhood that anything will be lost either.

Side A:
The clip uses all three clips on the socket on each side to grab hold and requires a screwdriver to engage it. The other end of the clip is held in position by the aluminum fan shroud to prevent the heatsink from being mounted at an angle on the silicon core. The fan shroud is screwed into the base to hold it firmly in place.

Side B:
From the side you can see right through the 0.61mm thick aluminum fins which are spaced 1.55mm apart according to manufacturer specs. The fins have a slight curve to them, and as you can see the base rises up at the center by a few millimeters. The copper base plate is 3mm thick.

We measured the base with a straight edge and found it to be perfectly flat. The surface finish is smooth, but if you draw your fingernail over it you can feel some very faint machining marks. The shinny copper baseplate comes out of the box protected with a big sticker so there is little chance of it being damaged or scratched before you can install it. The base is undercut 1mm for socket cam arm clearance.