Plowshare Technologies, Inc. proposes to develop and evaluate CReSSmicro, a lightweight, portable device that measures puff topography (e.g., puff number, volume, duration, and inter-puff interval) while smokers are at home, work, or play. Plowshare Technologies developed and marketed the first commercially available lab-based smoking topography measurement product: the Clinical Research Support System(CReSS). CReSSmicro will apply Plowshare's proven technology to the design of a portable device that extends valid and reliable smoking topography measurement from the laboratory into smokers' natural environments. During Phase I, a prototype of the CReSSmicro device will be developed and evaluated in a laboratory-based feasibility study with 40 smokers. The study will focus on establishing the validity, reliability and user acceptance of the CReSSmicro system by comparing puff topography data collected via CReSSmicro with data collected using CReSS under several different conditions. A variety of other quantitative results and qualitative feedback from subjects will be evaluated to supplement the primary outcome variables and guide further product development. During Phase II, a second generation prototype will be developed and evaluated in a larger scale study.