"The Minus Pad extreme 2 consists of aluminum oxide, aluminum hydroxide, and aluminum powder. The different particle sizes of the materials allow even the smallest gaps in the carrier matrix to be filled with thermally conductive particles. This contributes to lower thermal interface resistance, as the surfaces (top and bottom) of Minus Pad extreme 2 contain more thermally conductive particles than its predecessor.
The Minus Pad High Compression thermal pads feature exceptionally high compressibility. This makes them particularly versatile in applications where a single pad needs to bridge varying height differences simultaneously. This is especially useful when modifying graphics cards with a GPU water block or when replacing thermal pads on GPU coolers, as a Minus Pad High Compression (HC Pad) can be used across different components such as VRAM, voltage regulators, and other contact surfaces."
Source: Thermal Grizzly