The tobacco industry spends over 90% of its multi-billion-dollar advertising and promotion budget at retail point-of-sale (POS). The most prominent source of POS tobacco advertising comes from the tobacco power wall, the large, expansive display of hundreds of different tobacco products typically located behind the cashier in full view of consumers. Adolescents are frequent visitors to POS retail stores and as such are at significant risk for having repeated exposures to the tobacco power wall. Such exposures can contribute to increases in adolescent tobacco use risk and actual product use. As such, reducing the effect of the tobacco power wall on adolescent tobacco use is a critical public health goal. Several options for curbing the potency of the tobacco power wall have been advanced. The first option is a reduction in the amount of space that a tobacco power wall may occupy. This action would reduce the size of the tobacco power wall by as much as half and as a result, occupy less visible space behind the cashier counter. The second option is a reduction in the total number of tobacco product units within brand that are displayed on the power wall. This action would permit only one example of each brand to be displayed rather than several (e.g., rather than 10 boxes of Marlboro Reds and 10 tins of Camel Frost Snus, there would be allowed only one package of each). The overall aim of this research is to experimentally evaluate the extent to which reducing the size of the tobacco power wall and the number of tobacco product units displayed influences tobacco use risk in adolescents. This experiment will take place in the RAND StoreLab (RSL), a life-sized replica of a convenience store that we developed to evaluate how altering aspects of tobacco promotion at POS influences tobacco use risk during simulated shopping experiences. The study will use a between-subjects design, in which adolescents are randomly assigned to shop in the RSL under one of three conditions: (1) Large power wall/ multiple product units displayed; (2) Small power wall/multiple product units displayed; and (3) Small power wall/Single product units displayed. We will consider the effect of these power wall alterations on risk of use of four classes of tobacco products: cigarettes, electronic nicotine delivery devices, cigarillos, and smokeless tobacco. Tobacco use risk will be indexed by: attention to the tobacco power wall, perceived tobacco use norms, perceived availability of tobacco products, and tobacco use intentions. We hypothesize that the combination of these regulatory options (i.e., a small tobacco power wall with single units of each product displayed) will most effectively diminish tobacco use risk. We will also evaluate whether gender and/or tobacco use experience moderate adolescents' reactions to the power wall regulatory options under investigation. The results of this study have the potential to provide critical proof-of-concept information on how shrinking...