Specifications include, but are not limited to: Project support in carrying out five (5) qualitative studies including interviews with ENDS enthusiasts, social media content analysis, focus groups, interviews with youth ENDS users and cognitive testing of quantitative study questions. The results of these studies will inform the development of a quantitative nationally representative survey to identify demographics, product use behavior (ENDS, cigarettes, and other tobacco products), type, brand and model of ENDS product used, product modifications, user motivation for modifying the product (novelty, curiosity, better hit, better craving relief, smoke tricks, better taste, etc.), user views on characteristics which determine what makes the products hard or easy to modify, and the degree to which this feature impacted their decision to use/purchase the particular product.