The success of microbicide products will derive from the synergy of their biological functionality and user acceptability. Biological functionality is the integrated result of safe and effective anti-HIV compounds incorporated into dosage forms or devices that successfully deliver those compounds to target tissues, fluids, and pathogens. Acceptability is a multi-factorial phenomenon that accounts for the personal, dyadic, product-related, and social contexts that potentiate - or not - a woman's decision to use a microbicide. Acceptability (assessed, in part, by the users' sensory perceptions of products during use) depends strongly upon dosage forms and/or delivery systems with biophysical functions and/or mechanical and materials properties that are most conducive to human use. Without both, microbicides' potential to decisively alter the public health impact of HIV/AIDS and other sexually transmitted infections will be largely limited. The current protocol will specifically study the impact of gel volume on user perceptions, as well as extend user perception scale development to include those properties and product "behaviors" experienced when using a vaginal film.