Thermal interface materials come in a wide variety of product types and price points. Having a basic understanding of their strengths, weaknesses, and applicability is key to successful selection of the best interface material for your application needs. This paper will explain the key differences between thermal greases, phase change materials (PCMs), thermal pads and films, adhesives, and alloy composite materials. This document is part three in a three-part series. Previous installments dealt with thermal performance data and non-thermal material property impacts on thermal performance.