Introduction: Since being brought to market in 2007, cigarettes with capsules in the filter that can be burst to change the flavour have had remarkable global success, highlighting the importance of product innovation for tobacco companies. Very few studies have explored how these products are perceived by smokers however. This paper sought to address this gap by exploring smokers' awareness of cigarettes with one or two flavour-changing capsules in the filter and the appeal of these products. Methods: Twenty focus groups were conducted in Glasgow and Edinburgh in 2015 with current smokers (N=120), segmented by age (16-17, 18-24, 25-35, 36-50, >50), gender and social grade. Results: Awareness, use and appeal of capsule cigarettes was greater among younger adults (16-35 years), who showed most interest in these products. Those who perceived capsules positively mentioned multiple benefits: the ability to burst the capsule, convenience of being able to share cigarettes among menthol and non-menthol smokers, better taste, fresher breath, reduced smell and greater discretion. It was suggested that capsule cigarettes, particularly the double capsule cigarette (which had two differently flavoured capsules in the filter), would encourage non-smokers to experiment with smoking and discourage smokers from quitting. Conclusions: The findings offer some reasons behind the global growth of the capsule cigarette segment.